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HYGIENE 

DENTAL  AND  GENERAL 


BY 

CLAIR  ELSMEEE  TURNER 

ASSISTANT    PROFESSOR    Or    BIOLOGY    AND    PUBLIC    HEALTH    IN    THE    MASSA- 
CHUSETTS INSTITUTE  OF  TECHNOLOGY ;    ASSISTANT  PROFESSOR 
OF    HYGIENE    IN    THE    TUFTS    COLLEGE    MEDICAL 
AND    DENTAL    SCHOOLS 


With  Chapters  on 
DENTAL  HYCIIENE  AND  ORAL  PROPHYLAXIS 

By  William  Rice 

Dean,  Tufts  College  Dental  School 


ST.  LOUIS 

C.  V.  MOSBY  COMPANY 

1920 


K; 


\  <>  I 


Copyright,  lf)20,  By  C.  V.  Mosby  Company 

(All  Rights   Reserved) 


Press   of 

C.   V .  Mosby  Company 

St.  Louis 


TO 
MY  MOTHER 

This  book  is 
Affectionately  Dedicated 


PEEFACE 

There  are  many  reasons  why  the  dentist  should  have  an 
authentic  and  fundamental  knowledge  of  hygiene.  Whether 
willingly  or  unwillingly,  he  is  placed  in  the  position  of  an 
adviser.  The  ordinary  practice  of  his  profession  is  not  alone 
concerned  with  the  hygiene  of  the  mouth.  Troubles  which  he 
is  endeavoring  to  prevent,  correct  and  improve,  affect  the  gen- 
eral health  and  are  reacted  upon  by  it.  Moreover  many  peo- 
ple consult  the  dentist  who  do  not  visit  a  physician  and  to 
most  of  these  he  is  a  "doctor"  who  is  expected  to  know  not 
only  the  facts  relating  to  infection,  but  also  the  rules  for 
health.  Many  a  practicing  dentist  can  testify  that  he  is 
questioned  on  every  health  problem  from  diet  to  municipal 
sanitation. 

How  much  ought  the  dentist  to  know  about  these  subjects? 
Obviously  he  should  have  the  most  definite  knowledge  avail- 
able upon  the  interrelationship  between  abnormal  conditions 
of  the  mouth  and  other  organic  and  systemic  defects.  His 
knowledge  of  the  danger  of  transmitting  disease  in  dental 
practice  should  be  equally  definite.  The  rules  of  personal 
hygiene  are  of  use  to  him  not  only  in  regulating  his  own 
living  but  also  in  getting  the  best  results  with  his  cases.  To 
prescribe  a  schedule  of  hygienic  living  will  often  do  as  much 
as  an  office  treatment  in  getting  the  patient  into  a  normal  con- 
dition. 

Public  health  activities  also  have  a  right  to  claim  the  at- 
tention of  the  dentist.  He  is  coming  to  take  an  increasingly 
larger  part  in  municipal,  school  and  industrial  Hygiene  and 
he  should  know  the  powers,  organization  and  responsibility 
of  the  liealth  agencies  of  the  government.  But  apart  from 
these,  fields  in  wliich  ho  is  interested  professionally  he  has 
special  duties  of  citizenship,  for  his  training  has  given  him  a 
basis  for  appreciating  the  value  of  hygiene  and  sanitation. 
Excepting  possibly  the  physician  and  sanitarian  no  one  in 
the  community  can  so  well  understand  the  possibilities  and 

5 


b  PEEFACE 

advantages  of  efficient  public  health  administration.  The 
dentist  may  well  be  expected  to  assume  some  degree  of  lead- 
ership in  these  matters  and  if  he  is  able  to  do  so  successfully 
his  standing  in  the  community  is  markedly  benefited  both 
socially  and  professionally. 

There  has  hitherto  been  no  treatment  of  the  subject  of  hy- 
giene specially  prepared  to  meet  the  needs  of  the  dental  pro- 
fession. In  writing  this  book  for  the  dental  student  and  prac- 
titioner, special  attention  has  been  given  to  those  phases  of 
the  subject  which  relate  to  dental  practice  wherever  they 
occur. 

In  arranging  the  order  of  the  text,  those  aspects  of  both 
dental  and  personal  hygiene  that  are  not  related  to  infection 
are  first  considered.  Then  follows  a  discussion  of  the  de- 
velopment of  the  new  science  of  disease  prevention  and  its 
effect  upon  dental  practice,  personal  hygiene,  and  the  public 
health. 

The  author  desires  to  acknowledge  gratefully  the  assistance 
received  from  many  persons  in  the  criticism  of  the  manu- 
script. In  particular  thanks  are  due  to  Professor  Percy  G. 
Stiles  of  the  Harvard  Medical  School  for  reading  some  of  the 
manuscript  on  personal  hygiene  and  for  assisting  in  the  prep- 
aration of  a  diagram  of  the  autonomic  nervous  system. 
Special  thanks  are  also  due  to  -Dr.  F.  H.  Slack  for  reading 
the  chapter  on  immunity,  to  Dr.  F.  A.  Woods  for  suggestions 
in  connection  with  the  material  on  heredity,  to  Dr.  A. 
LeRoy  Johnson  for  assistance  in  the  chapter  on  oral  hygiene, 
and  to  other  teaching  associates  for  stimulating  and  helpful 
suggestions. 

The  author  also  wishes  to  express  appreciation  to  Professor 
C.-B.  A.  Winslow  for  permission  to  use  cuts  number  6,  9,  10, 
29  and  31  from  Healthy  Living,  to  Dr.  Lawrence  Baker  for 
permission  to  use  cuts  number  3  and  4  from  one  of  his  unpub- 
lished researches,  and  to  the  many  others  who  have  assisted  in 
securing  illustrative  material.  p    -p    m,,  „„„ 

Massachusetts  Institute  of  Technology, 
Cambridge,  Mass. 


CONTENTS 

CHAPTER  I 
DENTAL  HYGIENE 

PAGE 

The  Divisions  of  Personal  Hygiene — Hygiene  of  the  Mouth — The 
rorm  and  Arrangement  of  the  Teeth — Contact  and  Occlusion 
— Orthodontia — Function — Deforming  Habits — Structure  of 
the    Teeth — The   Investing   Tissues — The    Saliva 17 

CHAPTER  II 

THE   HYGIENE   OF   NUTRITION 

Diet  —  Water  — i  Nitrogenous  Foods — Carbohydrates — Fats — Inor- 
ganic Salts — Vitamincs — Dietary  Diseases — Balanced  Diet — 
The  Varied  Diet — Digestion — Digestion  and  the  Emotions — 
The  Hygiene  of  the  Emotions — Mastication — Water  with 
Meals — ^Rest  after  Eating — ^Assimilation — Assimilation  Defined 
— Oxidation — Eliminating  the  Body  Wastes — Autointoxica- 
tion— Constipation — Food  Poisoning — Obesity —  Under-eating 
- — -Conclusions         33 

CHAPTER  III 

THE  HYGIENE  OF  ACTION 

Two  Kinds  of  Bodily  Activity — Exercise — Wliat  Exercise  Does 
for  the  Body — Types  of  Pliysical  Exercise — Rhythm  in  Exer- 
cise— Walking — Ordinary  Body  Activities — Figure — Round 
Shoulders — Carrying  the  Head  Forward — Spinal  Curvatures — 
Deformities  of  the  Feet — Ocular  Hygiene — Breathing — Bath- 
ing— Clothing        54 

CHAPTER  IV 

'  THE  HYGIENE,  OF   THE   CENTRAL  NERVOUS   SYSTEM 

Function — Concentration — Habit  —  Sleep  —  Dreams  —  Oliange  of 
Work — Sunday  Observance — Neurasthenia — Overwork — Emo*- 
tious — Bodily  Defects — Stimulants — The  Neurasthenic    ...       68 

CHAPTER  V 

THE  HYGIENE  OF  REPRODUCTION 

The  Problem  Defined — Heredity — Mcndelian  Inheritance — How 
Sex  in  Offspring  is  Determined — Sex  Linked  Characters — In- 
herited Diseases  and  Abnormalities — Mentality  and  Heredity 
— Feeblc-mindedness — Heredity  and  Conduct — Prenatal  Care — 


8  CONTENTS 

PAGE 
Standards  for  Maternity  Care — Infant  Care — The  Obligation 
of  the  Community  to  the  Infant  and  the  Preschool  Child — Sex 
Hygiene — Sex   Education — Summary — The    Child's    Ten   Com- 
mandments to   Parents 80 

CHAPTER  A^I 

THE  NEW  SCIENCE  OF  DISEASE  PREVENTION 

Communicable  Diseases — Early  Theories  of  Disease — Fore-shadow- 
ings  of  the  Present  Theory — Fermentation  and  Disease — 
Pasteur — Lister — Koch  and  the  Development  of  Bacteriology^ 
— Preventive  Medicine — Smallpox  and  Vaccination — Immunity 
in  Anthrax  and  Rabies — 'Diphtheria  and  Antitoxin — Preven- 
tive Sanitation — The  Epidemic  of  the  Broad  Street  Well — A 
Typhoid  Fever  Epidemic  from  Oysters — Preventive  Hygiene 
— Resistance — Summary 108 

CHAPTER  VII 

THE  ESSENTIAL  FACTS  OF  IMMUNITY 

Imnuuiity  Defined — Nonspecific  Immunity — Fatigue — Exposure  to 
Wet  and  Cold — Drugs — Under-eating — Oral  Defects — Specific 
Immunity — Natural  Immunity — ^Local  Immunity — Acquired 
Immunity — Active  and  Passive  Immunity — Carriers — Disease 
Reactions — Toxins — Endotoxins^Reactive  Phenomena — Phag- 
ocytosis— Anaphylaxis — Specific  Substances — Theories  of  Im- 
munity— Exhaustion  Theory — Retention  Theory — Phagocytic 
Theory— Side    Chain    Theory '     .     .     .     \     .     126 

CHAPTER  VIII 

ORAL  PROPHYLAXIS 

Caries — Diet  in  Relation  to  Decay — The  Care  of  the  Gums  and 
Gingivae — Gingivitis  —  Deposits  —  Prophylactic  Treatment — 
The  Dental  Hygienist — Daily  Care  of  the  Teeth — Method  of 
Brushing  the  Teeth— Care  of  the  Brush— Dental  Floss— Tooth- 
picks— Mouth  Washes — Tooth  Powders  and  Pastes — Tooth 
Cleansing  Foods — Care  of  the  Mouths  of  Children — Septic 
Teeth  as  a  Source  of  Systemic  Disease     .     .     .     .     .     .     .     .     144 

CHAPTER  IX 

COMMnNlCAP.iiE  DISKASbiS 

Three  Gnat  Plague.s — Tuborcnldsis—  I'rovalciiro  -The  Difliculties— 
Transmission  of  Tiilicn-ulosis — Prevention  and  Control — Syph- 
ilis— Importance — Nature  of  the  Disease — Transmission — Tm- 
nnmity — Prevention — E(hicational  Program — Common  Cold — 
Tiic  Cause  of  Colds — Catcliing  Cold — Inlluenza — Cause — Mor- 
bidity and  Mortality  Rates — Immunity — Control 16.3 


CONTENTS  y 

PAGE 

CHAPTER  X 

PUBLIC  HEALTH  ADMINISTEATION 

Puljlic  Health  Authority — ^Fcderal  Public  Health  Functions — The 
Power  to  Regailate  Commerce — Taxation — ^Defense  and  Wel- 
fare Powers — Treaty  and  War  Powers — The  XJ.  S.  Public 
Health  Service — Other  Federal  Agencies — State  Health  Func- 
tions— Public  Health  Laws — State  Health  Administration — Or- 
ganization— Administrative  Functions — Local  Health  Adminis- 
tration— Authority — Local  Health  Organization — The  Health 
Officer— Unofficial    Health    Activities 188 

CHAPTER  XI 

FOOD  CONTROL 

Food  Adulteration — Cost  of  Adulteration — Nature  and  Cause  of 
Adulteration — Pure  Food  LaAvs — Misbranding — Law  Enforce- 
ment— Food  Sanitation — Milk — Graded  .Milk — Remade  Milk — 
Meat — Dangers    in    Meat — Prepared    Food 209 

CHAPTER  XII 

WATER  SUPPLY 

What  Is  Good  Water — Sources  of  Water  Supply — ^Water  Analysis 
— Environment  — ■  Bacteriological  Study  —  Physical  Tests — 
Chemical  Tests — Nitrogen  and  the  Nitrogen  Cj^cle — Chlorine — 
Microscopic  Analysis — Water  Purification — Storage — Filtration 
— Chlorination .' 226 

CHAPTER  XIII 

WASTE   DISPOSAL 

Sewage  Disposal — Direct  Disposal — -.Chemical  Purification — Bac- 
teriological Purification — Aerobic  Processes — Anaerobic  Proc- 
esses— Possibilities  and  Limitations  of  Sewage  Purification — 
Rural  Sanitation— Report  of  the  A.  P.  H.  A.  Committee     .     .     243 

CHAPTER  XIV 

SCHOOL  HY(!1KXK 

The  I'lulileni — Sp-cial  Groups  of  !)efecti\es- -The  Scope  of  Scliool 
Hygiene — Health  Control — Personnel — Physical  Examination 
— Treatment — Administration — Defective  Vision — The  Dental 
Care  of  ScIuhiI  Chihlren — Teaching  Hygiene  in  Schools — 
School  Hygiene  and  Sanitation — Ago  anil  Sex  DiiTerences — 
Standards 274 


10  CONTENTS 

PAGE 

CHAPTEE  XV 

INDUSTEIAL  HYGIENE 

General  Aspects  of  Industrial  Hygiene — General  Problems — Hours 
of  Work — Fatigue — Child  Labor — Women  in  Industry — Fac- 
tory Inspection — Health  Administration  in  Industi-y — Accident 
Prevention — Industrial  fSanitation —  Food — Medical  Activities 
— Industrial  Dentistry — Disease  Prevention  and  Health  Edu- 
cation^— -Industrial  Diseases — Lead  Poisoning — Phosphorus 
Poisoning — Mercury  Poisoning — Benzene  Compounds — Acids 
— Protection   against   Industrial   Poison 301 

CHAPTEE  XVI 

VENTILATION,   HEATING  AND   LIGHTING 

Good  Air  Defined — Temperature — Moisture — Odors — Testing  Air — 
The  Sling  Psychrometer — The  Hygrodeik— -The  Polymeter — 
The  Comfort  Meter — ^Ventilation  and  Heating — -Natural  Ven- 
tilation— Artificial  or  Mechanical  Ventilation- — Moisture  in  the 
Air — Air  Washing  and  Humidifying  Cooling  Air — The  Eco- 
nomic Value  of  Good  Ventilation — Lighting — Office  Lighting     .     323 

APPENDIX  A 

THE  CONTEOL  OF  COMMUNICABLE  DISEASES 

The  American  Public  Health  Association  Committee  Eeport  upon: 
Actinomycosis- — Acute  Infectious  Conjunctivitis — Anchylosto- 
miasis  (Hookworm) — Anthrax — 'Cerebrospinal  Meningitis — 
Chicken  Pox  —  Cholera  —  Dengue  — <  Diphtheria  —  Dysentery 
( Amebic )  — Dysentery  ( Bacillary )  — Favus — German  Measles — 
Glanders  —  Gonorrhea  • —  Leprosy — Malaria — Measles — Mumps 
— Paratyplioid  Fever — Plague — Pneumonia  (Acute  Lobar)  — 
Poliomyelitis — Eabies — Rocky  Mountain  Spotted  or  Tick  Fe- 
ver— Scarlet  Fever — Septic  Sore  Throat — Smallpox — S;y7)hilis — 
Tetanus — Trachoma — Trichinosis — Tuberculosis  (Pulmonary) 
— Tuberculosis  (Other  than  Pulmonary) — Tjq^hoid  Fever — 
Typhus  Fever — Whooping  Cough — YeUow  Fever     .     . '   .     .     .     339 

APPENDIX  B 

DISINFECTION  AND  DISINFECTANTS 

Definitions — Disinfection  versus  Sterilization — Antiseptics — Deodo- 
rants— Fumigation — Disinfection — Control  of  Disinfection — 
Natural  Disinfection — The  Ideal  Disinfectant — Standardizing 
Disinfectants — Physical  Agents  of  Disinfection — Gaseous  Dis- 
infection— Formaldehyde  Gas — Suljijhur  Dioxide — Oxygen — Hy- 
drocyanic Acid — Liquid  Disinfectants — Mercuric  Chloride — 
Formalin — Potassium  Permanganate — Lime — Whitewash — Milk 
of  Lime — Disinfection  in  Dental  Practice — Hands —  Materials 
—The   Office 378 

Bibliography 389 

Index 394 


ILLUSTRATIONS 

FIG.  PAGE 

1.  Model  illustrating  normal  occlusion 20 

2.  Model  illustrating  normal  occlusion 21 

3.  Asymmetric  development  of  the  boues  of  the  skull  of  a  dog     .  22 

4.  Upper  aspect  of  the  skull  shown  in  Fig.  3 23 

5.  Deformity   from    lack    of    function 24 

6.  Air  passages  of  the  mouth  and  nose  showing  their  relationship 

to  the  adenoids  and  tonsils 25 

7.  Deformity    due    to    thumb    sucking 26 

S.  Diagi-am  illustrating  groups  of  fibers  of  the  gingivae  and  peri- 
dental membrane 29 

9.  The  composition   of   cow's   milk 40 

10.  Portions   of   different   foods   each  yielding   approximately   100 

calories  of  heat  energy 41 

11.  Diagram  showing  the  most  important  distributions  of  the  auto- 

nomic nervous  system 46 

12.  The   worry-auto-intoxication   cycle 50 

13.  Good  and  bad  postures 60 

14.  Posture  chart  showing  the  result  of  the  examination  of  Har- 

vard  Freshmen 61 

15.  Inheritance  in  guinea  })ig  showing  where   one  color  dominates 

over  another  color '  .  SI 

16.  Diagram  illustrating  the  mechanism  by  which  the  unit  factor, 

color^  is  inlierited  in  guinea  pigs 83 

17.  Eminent   twins 84 

18.  Transmission   of   color  blindness 87 

19.  Cholera  deaths  in  the  epidemic  of  the  Broad  Street  Well     .     .  119 

20.  Diag'ram  illustrating  tlie  three  orders  of  immunity  as  deseriljed 

in  Ehrlich  's  Side  Chain   Theory   of  Immunity 141 

21.  Deformity  resulting  from  neglect  of  the  teeth 144 

22.  Showing   malocclusion    due    to    caries 145 

23.  Diagram  illustrating  nomenclature  of  gingivae 149 

24.  Diagram  illustrating  nomenclature  of  gingivae 149 

25.  Dental  hygienists  in  Prophylactic  Clinic  at  Forsyth  Dental  In- 

firmary  for    Children 154 

26.  Tooth  brushes  of  proper  shape  and  material 158 

11 


12  ILLUSTRATIONS 

FIG.  PAGE 

27.  Comparative  figures  showing  the  number  of  disease  and  battle 

deaths  each  yeai*  per  thousand  trooj^s  in  the   wars  of  the 
United    States 166 

28.  The  relative  proportion  of  army  deaths  caused  by  the  principal 

diseases  in  the  war  with  Germany 167 

29.  An  inexpensive  and  easity  constructed  outdoor  sleeping  porch     .     173 

30.  Chart  showing  the  time  and  temperatures  at   which  bacteria 

are  killed  and  at  which  the  quality  of  the  milk  is  changed     .     217 

31.  Pasteurization  of  milk  at  home 218 

32.  Pollution  of  wells  by  water  which  soaks  through  the  soil  from 

privies  or  cesspools 229 

33.  The  nitrogen  cycle 232 

34.  Diagram  showing  the  condition  of  the  stream  studied  at  Brock- 

ton        237 

35.  Diagram  showing  the  abundance  of  microorganisms  at  the  va- 

rious  sampling   stations 238 

36.  Shows  how  completely  the  higher  aquatic  plants  fill  part   of 

stream  in  summer 239 

37.  Showing  how  differently  the  same  region  appears  under  winter 

conditions  and  high-stream  flow 239 

38.  A  chemical  closet  installed  in  a  home  where  running  water  is 

not  available 245 

39.  Eemoving  the  sludge  from  the  sand  beds  at  the  Brockton  Sew- 

age Purification  Works 248 

40.  Imhoff    tank .252 

41.  Sewage  purification  plant   in  Atlanta,   Gfa. 254 

42.  A  single-seated  sanitary  privy 260 

43.  Eear  and  side  view  of  privy 261 

44.  Outdoor  incinerator   (Arnold  type) 268 

45.  Floor  plan  and  arrangement  of  medical  inspector's  room  gen- 

erally followed  in  New  York  City 281 

46.  The  effect  of  treatment  for  adenoids  upon  the  general  appear- 

ance  of  three   children 284 

47.  Errors  in   refraction 285 

48.  Dental  Clinic  at  the  Forsyth  Dental  Infirmary  for  Children     .  290 

49.  Wet  and   dry  bulb   thermometer 327 

50.  Wliiig    iisycIiroiiK'tcr "^'^ 

51.  Hygrodeik    instrument        .     : -^29 

52.  Portable  foot  candlemeter 338 


FOREWORD 

By  William  T.  Sedgwick,  Sc.D. 

Professor  of  Biology  and  Public  Health,  Massachusetts  Institute  of 

Technology,   Chairman  Harvard-Technology  School  of 

Public  Health,  etc. 

Whoever  regards  the  human  mechanism  objectively  cannot 
fail  to.be  struck  with  the  growth  and  function  of  its  harder 
parts.  Bones,  nails  and  teeth,  though  wanting  in  the  early 
embryo,  are  rapidly  formed  soon  after  independent  life  begins. 
The  bones,  securely  covered,  are  rarely  exposed  to  decay  or 
wear,  and  the  skeleton  in  age  is  in  many  respects  more  com- 
plete and  perfect  than  in  youth.  But  with  the  teeth  it  is 
otherwise.  Pushing  outwards  through  the  soft  parts  these 
are  very  early  exposed  to  unfavorable  conditions  and,  like 
knives  and  millstones,  become  dull  and  worn  with  use.  Even- 
tually, if  not  forcibly  removed  they  fall  out,  so  that  at  the  end 
of  life  man  is  often  "sans  teeth,"  though  not  "sans  every- 
thing"— no  other  organs  of  the  body  except  the  hair  and  epi- 
dermis being  thus  deciduous. 

Hence  it  is  that  the  teeth  for  their  protection  require  un- 
usual care — a  fact  now  generally  recognized  by  the  rise  of  the 
dental  profession  and  the  popular  enthronement  of  the  tooth- 
brush. But  scientific  care  of  any  of  the  organs  of  the  body  is 
neither  more  nor  less  than  hj^giene,  so  that  Dental  Hygiene — 
the  scientific  care  of  the  teeth — is  one  of  the  fundamentals 
of  all  hygiene.  And  since  the  human  body  is  not  merely  an 
assembly  of  discontinuous  and  unrelated  parts,  but  rather  a 
complete  entity  or  organism — originally  homogeneous  and 
never  more  than  incompletely  differentiated — so  much  so  that 
the  hand  cannot  say  to  the  foot,  or  the  brain  to  the  teeth, 
"I  have  no  need  of  thee" — it  follows  that  dental  hygiene  is 


14  ^  FOREWORD 

only  a  part  of  General  Hygiene.  Accordingly,  while  this  book 
deals  with  the  hygiene  of  the  teeth  and  takes  its  beginnings 
with  the  teeth  it  does  not — ^because  it  cannot — end  there. 
Foods  and  feeding,  the  flow  of  saliva,  the  blood  stream  and  the 
lymph  drains  and,  more  remotely  but  not  less  surely,  sleep 
and  rest,  work  and  play,  muscular  activity  and  mental  fatigue 
— all  these  and  many  more  aspects  of  general  hygiene  con- 
tribute to  the  welfare  of  the  teeth.  Conversely,  the  health  or 
disease  of  the  teeth  plays  an  all-important  part  in  the  wel- 
fare of  the  other  organs  of  the  body  and  of  the  body  as  a 
whole,  as  all  know  who  have  been  incapacitated  by  acute 
toothache. 

Professor  Turner's  is  the  first  work  which,  taking  for  its 
principal  field  the  hygiene  of  a  single  set  of  organs,  reaches 
out  from  these  to  the  rest  of  the  body.  And  perhaps  it  is 
for  this  reason  that  our  textbooks  of  hygiene  have  so  often 
hitherto  been  comparatively  uninteresting  and  ineffective. 
It  may  be  that  they  have  been  too  general  and  in  seeking  to 
tell  all  things  about  hygiene  have  failed  to  tell  any  well.  It 
is  for  this  reason  among  many  that  I  predict  for  this  work 
an  unusually  hearty  welcome,  for  those  who  read  it  attentively 
will  find  that  while  the  text  of  the  sermon  is  dental  hygiene, 
and  while  the  teeth — as  in  the  speaking  human  face — are  al- 
ways near  and  much  in  evidence,  the  lessons  taught  apply 
quite  as  well  to  the  entire  human  body  and  its  effective  con- 
servation. Such  conservation,  however,  not  only  requires 
careful  consideration  of  the  human  body  but  of  that  environ- 
ment with  which  the  body  deals  and  which  plays  upon  it  from 
birth  to  death. 

Fifty  years  ago  the  slogan  for  health  was  mens  sana  in 
corpore  sano — an  admirable  aphorism  but  one  curiously  typ- 
ical of  a  neglect  of  environment  characteristic  of  the  pre- 
Darwinian  period.  Nowadays  we  know  only  too  well  that 
the  sound  mind  and  the  sound  body  are  unavailing  for  the 
conduct  of  normal  living  unless  the  environment  with  which 


FOREWORD  15 

they  have  to  deal  consists  of  fairly  good  air,  fairly  pure  water, 
fairly  good  food,  and  is  fairly  free  from  conununicable  dis- 
eases, unfavorable  temperatures,  defective  ventilation,  dirt, 
noise  and  other  prejudicial  sanitary  conditions.  Hence,  Pro- 
fessor Turner  surveying  the  whole  field  of  dental  and  general 
hygiene  has  found  it  necessary  to  reach  out  beyond  the  teeth 
and  other  organs  of  the  body,  and  even  beyond  the  body  itself, 
to  a  consideration  of  those  environmental  factors  which  con- 
tribute so  heavily  to  health  or  disease,  with  the  result  that  his 
work  is  not  merely  novel  and  comprehensive,  but  also  original, 
logical  and  representative  of  the  best  hygienic  thought  of  the 
time. 


HYGIENE:   DENTAL  AND  GENERAL 


CHAPTER  I 
DENTAL  HYGIENE 

Hygiene  or  the  science  of  healthful  living  furnishes  to  man 
the  baKsis  for  a  rational  control  over  .those  habits  and  con- 
ditions of  existence  which  affect  for  good  or  ill  the  smooth 
and  normal  operation  of  the  body  mechanism.  The  develop- 
ment of  healthful  habits  of  life  depends  primarily  upon  the 
i]idividual,  but  the  maintenance  of  healthful  living  conditions 
is  largely  beyond  individual  control,  and  the  responsibility 
rests  upon  organized  society.  In  the  restricted  sense  hygiene 
considers  the  health  of  the  individual,  sanitation  the  control 
of  the  environment. 

In  considering  the  hygiene  of  both  the  mouth  and  the  body 
as  a  whole  there  are  two  distinct  sets  of  problems:  (1)  the 
proper  development  and  normal  functioning  of  the  pails  and 
(2)  the  problems  arising  because  of  infectious  organisms.  In 
this  book  the  two  subjects  are  separated,  the  first-mentioned 
receiving  consideration  in  the  first  five  chapters. 

The  Divisions  of  Personal  Hygiene. — Personal  Hygiene  as 
contrasted  with  public  hygiene  or  public  health  considers 
those  principles  and  activities  for  the  promotion  of  health 
over  which  the  individual  has  control,  and  to  determine  the 
scope  of  this  science  we  have  to  consider  the  functions  of  man 
as  an  animal.  In  blunt  and  simple  language  nature  has  de- 
creed that  man  shall  eat,  work,  think,  and  breed.  The  zo- 
ologist expresses  this  idea  more  elegantly  and  scientifically 
by  saying  that  the  particular  functions  of  animals  are  assim- 
ilation, action,  sensation,  and  reproduction.  Accepting  either 
set  of  terms  in  their  broad  sense  we  may  group  the  problems 
of  Pei^onal  Hygiene  under  these  four  heads : 

17 


18  HYGIENE:     DENTAL   AND   GENERAL 

1.  Hygiene  of  Nutrition. 

2.  Hygiene  of  Action. 

3.  Hygiene  of  the  Central  Nervous  System. 

4.  Hygiene  of  Reproduction. 

HYGIENE  OF  THE  MOUTH 

The  subject  of  Hygiene  concerns  the  health  of  the  body 
in  all  its  parts  and  there  is  no  natural  division  which 
makes  it  necessary  to  consider  any  particular  portion  of  the 
body  under  a  separate  head;  nevertheless  Dentistry  is  such 
a  distinct  and  highly  specialized  subject  that  it  will  certainly 
be  profitable  to  treat  the  hygiene  of  the  mouth  in  detail  and 
apart  from  the  above  mentioned  divisions,  for  the  dentist's 
interest  is  of  necessity  centered  upon  oral  conditions  and,  for 
this  reason,  he  should  be  able  to  speak  with  authority  upon 
the  means  available  for  the  preservation  of  the  health  of  the 
various  oral  structures  and  of  the  relationship  of  oral  health 
to  the  general  well-being  of  the  entire  organism.  We  are 
perhaps  warranted  therefore  in  adding  another  division  of 
the  subject  for  the  purposes  of  this  volume,  namely  the  Hy- 
giene of  the  Mouth. 

In  the  treatment  of  this  subject  it  seems  desirable  to  con- 
sider it  under  two  heads:  (1)  Proper  development  and  nor- 
mal functions  of  the  oral  structures  (Chapter  I),  and  (2)  The 
treatment  and  prevention  of  unhygienic  or  septic  conditions 
(Chapter  VIII). 

We  will  consider  the  means  provided  by  nature  for  the 
maintenance  of  oral  health  under  four  headings,  as  follows: 

1.  Form  and  arrangement  of  the  teeth. 

2.  Structure. 

3.  Investing  tissues. 

4.  Saliva. 

1.  The  Form  and  Arrangement  of  the  Teeth  should  be 
such  that  their  relationship  offers  the  highest  degree  of  corre- 
lation ;  each  tooth  performs  its  functions  as  a  dependent  unit 


DENTAL    HYGIENE  19 

in  a  perfect  machine  operated  under  the  motive  power  of  the 
muscles  of  mastication. 

A  study  of  normal  conditions  is  necessary  and  a  concep- 
tion of  the  normal  should  be  constantly  held  in  mind  as  a 
definite  picture.  The  question  may  well  be  asked:  What  is 
the  normal?  Does  it  ever  exist  in  fact?  Johnson  defines 
normal  as  applied  to  morphology  as  signifying  "a  standard 
determined  by  constancy. ' ' 

The  teeth  are  in  four  classes,  incisors,  cuspids,  bicuspids 
and  molars,  each  class  designed  for  a  particular  function 
in  the  process  of  mastication.  The  type  or  form  of  the  teeth 
in  each  of  these  classes  varies  according  to  the  shape  of  the 
face  of  the  individual,  as  Williams  has  shown  in  his  classic 
work.  ("Classification  of  Human  Tooth  Forms,"  Journal 
of  the  Allied  Dental  Societies,  Vol.  IX,  No.  1.) 

Contact  and  Occlusion. — When  the  teeth  are  in  normal 
alignment  the  approximating  surfaces  of  the  teeth  in  each  jaw 
are  in  actual  contact  at  one  point,  known *as  the  contact  point. 
The  object  of  this  contact  is  the  protection  of  the  investing 
tissues.  This  is  accomplished  by  preventing  the  crowding  of 
food  into  the  interproximal  spaces.  Any  deviation  from  nor- 
mal alignment  or  the  loss  of  any  tooth  in  the  arch,  (with  the 
possible  exception  of  the  third  molar)  will  result  in  impair- 
ment of  function  and  a  loss  of  the  protection  to  the  in- 
vesting tissues;  and  opportunity  will  be  afforded  for  the 
crowding  of  food  material  between  the  teeth,  thereby  establish- 
ing a  condition  favorable  to  fermentation  and  putrefactive 
changes. 

The  alveolar  process,  which  is  the  bony  tissue  surrounding 
the  roots  of  the  teeth,  is  a  temporary  structure  designed  to 
furnish  support  to  the  teeth  while  present  within  the  jaw.  It 
is  built  up  around  the  roots  of  the  teeth  as  they  develop  after 
the  eruption  of  their  crowns  and  is  removed  by  the  process 
of  absorption  after  the  loss  of  any  tooth.  It  follows,  there- 
fore, that  after  the  premature  loss  of  a  tooth  and  the  removal 
of  its  supporting  process,  no  stimulus  remains  for  bone  devel- 


20  HYGIENE:     DENTAL   AND   GENERAL 

opment;  the  continuity  of  the  entire  arch  is  broken  and  the 
teeth  tend  to  drift  in  the  direction  of  least  resistance.  This 
results  inevitably  in  the  loss  of  the  normal  relationship  be- 
tween the  approximating  surfaces  of  the  teeth  of  each  jaw 
as  well  as  the  occlusal  relationships  of  the  teeth  in  opposing 
jaws.     Serious  deformity  may  follow. 

Smith  has  shown  {Journal  of  the  Allied  Dental  Societies, 
Vol.  I,  April,  1906)  that  in  certain  cases  of  malocclusion  the 
timely  and  well  judged  extraction  of  teeth  may  result  bene- 
ficially by  relieving  the  crowded  condition.  The  tendency  of 
the  drift  may  then  bring  the  surfaces  of  the  remaining  teeth 
into  positions  closely  simulating  the  normal. 


Fig.    1. — Model    illustrating    normal    occlusion. 

Orthodontia. — We  agree  with  Johnson  that  the  attainment 
of  the  ideal  normal  occlusion  of  the  teeth  by  orthodontic 
interference  is  not  always  possible  and  in  many  cases  an 
attempt  to  bring  this  about  will  result  in  an  inharmony  in 
the  relationship  of  the  teeth  to  the  general  contour  of  the 
bony  and  muscular  structures  of  the  face  which  nature  will 
not  tolerate.  Not  only  will  it  be  impossible  to  retain  the  teeth 
in  their  new  position,  which  is  an  abnormal  one,  but  there 
may  ultimately  result  a  deformity  more  objectionable  than 
the    original    condition.      Extensive    orthodontic    treatment 


DENTAL   HYGIENE  21 

should  be  undertaken  only  after  a  careful  study  of  all  pre- 
vailing conditions  by  one  whose  vision  is  not  limited  to  the 
teeth  alone.  It  is  futile  to  attempt  to  permanently  establish 
ideal  normal  occlusion  when  all  the  forces  of  nature  are  being 
exerted  to  maintain  the  position  of  the  teeth  in  their  relation- 
ship to  the  organism  as  a  whole. 

Development. — Let  us  revert  to  the  period  of  development. 
Baker  has  shown  in  his  researches  upon  animals  that  the 
normal  development  of  the  dental  arches  is  dependent  upon 
the  presence  within  the  jaw  of  the  developing  teeth.  The 
development  of  the  bone  is  synchronal  with  the  development 
of  the  roots  of  the  teeth.  The  removal  of  the  teeth  from  one 
side  of  the  jaw  was  shown  to  cause  an  arrested  development 
of  the  bone  which  resulted  in  marked  deformity.  The  in- 
.harmony  of  the  side  of  the  face  from  which  the  teeth  were 
removed  was  very  apparent.     It  Avas  further  demonstrated 


Fig.    2. — Model   illustrating   normal    occlusion. 

that  normal  development  of  the  entire  bony  structui'e  of  the 
head  is  to  a  certain  extent  dependent  upon  the  proper  develop- 
ment of  the  teeth. 

Function. — Among  the  causes  of  malocclusion  must  be  con- 
sidered tlie  dependence  of  development  upon  function.  For 
instance,  a  study  of  the  organs  of  mastication  of  the  anthro- 
poid ape  (man's  prototype)  reveals  massive  structure,  de- 
manded by  the  functional  activity  incident  to  the  mastication 
of  the  kind  of  food  available  for  his  sustenance  and  upon 
which  his  existence  depended. 


22 


HYGIENE :    DENTAL   AND    GENERAL 


With  the  development  of  modern  methods  for  refining  the 
raw  materials  to  be  used  as  food  and  the  acquirement  of  the 
epicurean  habit — which  demands  the  preparation  of  complex, 
highly  seasoned  food  calculated  to  stimulate  pleasurable  sen- 


Fig.  3. — Observe  the  asymmetric  development  of  the  bones  of  the  skull  of  a 
flog  due  to  the  interference  with  the  function  of  the  upper  left  lateral  half 
of  the  dental  apparatus. 


sations  in  those  whose  appetites  are  already  satiated  by  over- 
indulgence— the  necessity  for  vigorous  muscular  effort  has 
been  removed  and  the  stimulating  effect  of  vigorous  function- 
ing has  been  lost.     The  lower  part  of  the  face  has  thus  been 


DENTAL   HYGIENE 


23 


reduced  in  size  but  the  teeth  have  not  relatively  changed.  The 
result  is  that  the  teeth  of  many  people  are  out  of  harmony  in 
size,  with  the  rest  of  the  features. 

All  variations  from  the  normal  in  the  development  of  the 


Fig.    4. — Upper    aspect    of    the    skull    shown    in    Fig.    3. 

various  units,  which  are  interdependent,  must  of  necessity 
affect  the  proper  functioning  of  the  organism  as  a  whole  and, 
therefore,  become  problems  in  hygiene. 

Although  there  is  a  difference  of  opinion  on  this  subject. 


24 


HYGIENE :     DENTAL   AND    GENERAL 


there  are  orthodontists  who  believe  that  the  normal  develop- 
ment of  the  oral  structures  is  also  impeded  by  substituting 
the  artificial  feeding  of  the  infant  in  the  place  of  breast 
feeding.  "Whoever  has  observed  carefully  the  infant  in  the 
act  of  nursing  must  have  noticed  that  much  exertion  is  put 
forth  in  the  effort  to  obtain  the  milk.  It  is  upon  this  mus- 
cular effort,  and  the  enforced  position  of  the  oral  structures 
during  the  act  of  sucking  and  swallowing  that  normal  devel- 
opment is  in  a  considerable  degree  dependent.  No  bottle 
feeding  device  perfectly  simulates  the  breast  or  affords  the 


Fig.    5. — Deformity    from    lack    of    function.      Ankylosis    prevented    the    movement 

of  the  jaw. 

vital  muscular  resistance  which  supplies  the  essential  stimu- 
lus for  the  development  of  the  oral  structures  of  the  growing 
infant. 

Deforming  Habits. — Deformities  of  the  face  and  jaws  aris- 
ing from  mouth  breathing  or  other  habits  contracted  in  in- 
fancy, such  as  thumb-sucking  and  the  continued  use  of  pac- 
ifying devices,  deserve  consideration. 

One  of  the  most  common  causes  of  mouth  breathing  is  the 
presence  of  adenoids  in  the  posterior  nares  which  so  fill  up 
the  space  required  for  normal  breathing  that  the  child  resorts 


DENTAL   HYGIENE 


25 


to  mouth,  breatliiug  in  order  to  obtain  sufficient  air.  Adenoids 
are  enlarged  lymphoid  follicles.  These  follicles  are  normally 
present  in  the  nasopharynx  but  from  various  sources  of  irri- 
tation they  frequently  become  congested  and  swollen. 

The  deformities  resulting  from  the  use  of  pacifying  devices 
are  frequently  seen;  and  their  use  either  reflects  upon  the 
intelligence  of  the  parents  or  they  are  used  in  utter  disregard 


Fig.    6. — The   air   passages   of   the   mouth   and    nose    showing   their    relationship    to 
the   adenoids    and    tonsils. 

of  the  welfare  of  the  child.  In  any  case  the  resulting  deform- 
ity is  a  constant  rebuke  to  the  neglect  of  the  child. 

The  thuml) -sucking  habit  may  be  overcome  by  binding  the 
arms  of  the  child  to  its  side  or  by  the  use  of  celluloid  hand 
protectors.  The  deformity  of  drawn-in  arches  which  results 
from  thumb-sucking  is  so  characteristic  as  to  be  unmistakable, 
and  not  only  interferes  with  the  functioning  of  the  teeth  but 
destroys  the  entire  contour  of  the  mouth. 

2.  Structure  of  the  Teeth. — Nature  has  protected  llie 
teeth  by  furnishing  for  their  outer  covering  the  hardest  sub- 


26  HYGIENE:     DENTAL   AND   GENERAL 

stance  to  be  found  in  the  body.  A  difference  in  opinion  exists 
in  regard  to  the  question  of  variation  in  the  hardness  of  the 
teeth  in  different  individuals  and  at  different  age  periods  of 
the  same  individual.  To  state  the  question  more  explicitly : 
are  some  teeth  hard  and  others  soft?  Is  this  hardness  or 
softness  of  the  teeth  subject  to  changes  at  different  periods  in 
life,  and  does  nutritional  action  affect  the  integrity  of  the 
enamel  rendering  it  more  susceptible  to  the  inroads  of  caries  ? 
Or  is  this  lesion  dependent  alone  upon  the  oral  secretions 


Fig.   7. — Deformity   due  to   thumb   sucking. 

which  are  really  determined  by  sj^stemic  conditions'?  A 
statement  of  the  conclusions  of  recognized  investigators  may 
aid  in  forming  an  opinion. 

Williams  has  stated  that  "enamel  is  a  solid  mineral  sub- 
stance and  the  finest  lenses  reveal  not  the  slightest  difference 
between  enamel  ground  moist  from  a  living  tooth  and  that 
which  has  lain  in  the  earth  for  hundreds  of  centuries."  This 
statement  would  not  seem  to  be  borne  out  by  analyses  of 
enamel,  for  according  to  statistics  published  from  time  to 
time,  the  amount  of  organic  matter  varies  from  two  to  seven 
per  cent. 


DENTAL    HYGIENE  27 

Pickerell  found  that  enamel  is  not  impermeable  and  that 
stain  penetrates  to  a  varying  depth  in  different  teeth ;  more- 
over, the  permeability  varies  in  ratio  to  the  length  of  time  a 
tooth  has  been  erupted.  This  would  seem  to  prove  that 
enamel  does  change  its  character  after  the  eruption  of  the 
teeth.  He  also  found  that  the  density  or  compaction  of 
enamel  was  in  direct  ratio  to  the  time  elapsed  since  its  for- 
mation. The  hardness  of  enamel  was  tested  by  determining 
the  comparative  resistance  to  scratching.  The  result  of  his 
experiment  seems  to  be  conclusive  that  there  does  exist  a  de- 
cided difference  in  the  hardness  of  teeth.  The  hard  teeth  he 
terms  sclerotic,  and  the  soft  teeth  malacotic.  He  believes  that 
the  permeability,  density  and  hardness  are  important  factors 
in  the  predisposition  to  caries  since  malacotic  teeth  would 
more  readily  permit  the  penetration  of  the  oral  fluids. 

Black  made  a  series  of  studies  published  in  the  Dental  Cos- 
mos in  1895  relative  to  the  hardness  of  teeth  as  a  whole.  His 
experiments  bear  special  reference  to  the  percentage  of  cal- 
cium salts  in  dentin,  and  as  the  initial  lesion  in  caries  always 
takes  place  in  the  enamel  his  conclusions  would  not  seem  to 
have  a  direct  bearing  on  the  susceptibility  of  teeth  to  caries. 
It  may  well  be  that  the  dentin  of  teeth  is  practically  uniform 
in  the  calcium  content. 

Black  asserts  that  the  seeming  differences  in  the  hardness 
of  teeth  as  reflected  by  their  varied  resistance  to  cutting  in- 
struments is  due  to  (1)  the  direction  of  approach,  (2)  to  the 
difference  in  the  relation  of  the  enamel  rods  to  each  other. 
Since  enamel  is  not  a  homogeneous  structure,  but  composed 
of  hexagonal  rods,  held  together  by  a  cementing  substance  less 
strong  than  the  rods,  it  is  possible  to  cleave  them  along  the  line 
of  their  length  more  easily  than  in  other  directions.  When 
the  rods  lie  parallel  with  each  other  the  enamel  splits  easily ; 
on  the  other  hand,  in  many  teeth  the  enamel  rods  do  not  run 
parallel  but  are  curled,  twisted  and  interwoven.  This  enamel 
would  cut  with  much  greater  difficulty  even  if  there  were  no 
difference  in  amount  of  calcium  salts  contained. 


28  HYGIENE:     DENTAL   AND   GENERAL 

Howe  in  his  experiments  upon  animals  has  actually  pro- 
duced caries  by  depriving  them  of  their  natural  food,  such  as 
green  vegetables,  milk  and  other  substances  rich  in  mineral 
content.  Whether  caries  was  caused  by  degeneration  of  the 
tooth  structure  due  to  lowered  nutrition  or  whether  the  nutri- 
tional disturbance  influenced  the  environment  (oral  secre- 
tions) is  a  question. 

From  a  clinical  standpoint  I  feel  sure  that  a  consensus  of 
opinion  would  be  that  the  character  of  the  hard  tissues  of  the 
teeth  does  vary  at  different  periods  in  life,  and  the  physical 
characteristics  of  the  teeth  are  affected  by  the  general  physi- 
cal condition  of  the  individual.  Whether  this  change  comes 
from  nutritive  disturbances  which  in  some  unknown  way 
affect  the  integrity  of  the  tooth  structure  through  the  blood 
stream,  or  whether  the  changes  are  solely  the  result  of  in- 
fluences from  without  is  yet  to  be  decided. 

3.  The  Investing-  Tissues. — The  teeth  are  set  in  the  alveolar 
process  which,  as  has  been  stated,  is  developed  simultaneously 
with  the  roots  of  the  teeth,  gradually  disappearing  when  its 
function  as  a  supporting  structure  ceases  to  exist.  It  is  the 
framework  upon  which  the  soft  investing  tissues  are  laid  and 
in  it  are  the  sockets  in  which  the  roots  of  the  teeth  are  set 
and  held  by  their  membrane.  It  envelops  the  roots  of  the 
teeth  and  develops  in  such  a  way  as  to  rise  to  a  considerable 
height  between  the  teeth,  forming  a  crest  known  as  the  alve- 
olar crest. 

The  peridental  membrane  is  the  term  applied  to  the  soft 
tissues  lying  between  the  root  of  the  tooth  and  the  walls  of  the 
alveolar  socket,  its  function  being  to  attach  the  teeth  to  the 
bone  of  the  jaw.  Various  groups  of  fibers  radiate  from  the 
peridental  membrane  to  the  gingivae  and  the  alveolar  process 
in  which  they  are  attached.  These  fibers  not  only  attach  the 
tooth  to  tlie  alveolar  bone  but  they  pass  from  tooth  to  tooth 
over  the  alveolar  crest  forming  a  continuous  chain  connecting 
the  teeth  from  one  extremity  of  the  arch  to  the  other.     These 


DENTAL   HYGIENE 


29 


fibers  have  the  effect  of  a  ligament  binding  the  roots  of  the 
teeth  to  the  bone.     It  will  be  seen  that  the  extraction  of  any 
tooth  literally  breaks  the  continuity  of  the  entire  arch. 
The  gingiva,  resting  on  -the  crest  of  the  alveolar  process 


^     i^^<^^    ^     ^ 


60 

Fig.  S.- — Diagram  illustrating  groups  of  libers  of  the  giugivx  and  peridental 
membrane.  Bucco-lingual  section  through  a  bicuspid  tooth  and  investing  tissue. 
F,  Free  gingivs  group  of  fibers;  Ac,  Alveolar  crest  group  of  fibers;  H,  Horizontal 
group  of  fibers;  O,  Oblique  group  of  fibers;  A,  Apical  group  of  fibers;  B,  Bone 
or  alveolar  process.     (Black's  "Special  Dental  Pathology.") 


30  HYGIENE:     DENTAL   AND   GENERAL 

encircles  each  tooth  and  rises  on  the  septal  crest  to  a  point 
below  and  near  the  contact  of  the  proximal  surface  of  the  ad- 
joining teeth.  This  tissue  hugs  closely  the  neck  of  the  tooth 
but  is  not  attached  to  it,  the  space  between  the  tooth  and  the 
tissue  being  known  as  the  sub-gingival  space.  Any  injury  to 
this  free  gingival  tissue  affects  seriously  its  protective  func- 
tion and  exposes  a  vulnerable  portion  of  the  tooth  to  the  acid- 
forming  bacteria,  while  the  crowding  down  of  the  septal  gin- 
giva affords  a  favorable  place  for  the  impaction  of  food 
material.  This  condition  frequently  leads  to  the  formation 
of  a  pocket  which,  becoming  infected,  gradually  destroys  the 
supporting  structure  of  the  teeth,  causing  tlieiv  loosening  and 
eventual  loss. 

4.  The  Saliva. — The  role  played  by  the  saliva  is  also  a 
very  important  one  among  the  defensive  or  protective  agen- 
cies, and  its  presence  and  constant  renewal  tends  to  maintain 
the  normal  environment  of  the  teeth  and  to  overcome  by  its 
neutralizing  effect  the  harmful  action  of  fermentation.  In 
general  terms  it  may  be  stated  that  the  saliva  is  composed  of 
water,  albumen,  mucus,  ptyalin  and  the  salts  of  potassium  and 
sodium  held  in  solution.  The  proportions  vary  in  different 
individuals  and  in  the  same  individual  at  different  periods  of 
the  day.  The  amount  of  its  different  components  will  be  af- 
fected by  the  physical  condition  of  the  individual  and  by  the 
kind  of  stimulation  inciting  its  flow. 

Cannon  has  shown  in  his  experiments  on  animals  that  the 
digestive  fluids  are  greatly  influenced  both  in  amount  and 
composition  by  the  mental  state  of  the  animal.  The  mental 
impression  produced  by  the  sight  or  odor  of  food  also  has  a 
similar  effect.  The  old  saying  that  a  certain  food  makes  the 
mouth  water  has  its  basis  in  fact.  The  mere  thought  of 
savory  food  or  acid  fruits  is  sufficient  to  stimulate  the  glands 
to  increased  functioning. 

Saliva  varies  also  in  its  physical  characteristics  from  a 
thick,  viscid,  mucilaginous  substance  rich  in  albumen  and 
mucus  to  a  thin  watery  fluid  containing  small  quantities  of 


DENTAL   HYGIENE  31 

colloid  material.  Carbon  dioxide  is  always  present  in  the 
saliva  as  in  the  blood  and  other  body  fluids. 

The  action  of  the  ptyalin  content  is  to  convert  starch  into 
sugar  during  the  process  of  mastication.  Thorough  masti- 
cation is  essential  to  obtain  the  full  effect.  The  sense  of 
taste  will  quickly  detect  the  change  taking  place,  the  sweet 
taste  increasing  as  the  chemical  action  proceeds.  According 
to  Black  the  ptyalin  has  a  still  further  function  in  freeing 
the  surfaces  of  the  teeth  and  the  embrasures  of  the  clinging 
particles  of  starchy  foods  which  remain  after  the  mass  has 
been  swallowed.  Pickerell  also  suggests  that  the  principal 
function  of  the  saliva  is  the  hydrolysis  of  the  starches. 

The  function  of  mucus  in  the  saliva  is  largely  a  mechanical 
one.  It  lubricates  and  makes  slippery  all  the  surfaces  of  the 
tissues.  It  coats  the  teeth  and  imparts  to  their  surfaces  a 
smoothness  and  softness  not  otherwise  obtainable.  During 
mastication  it  mixes  with  the  food  and  prevents  it  from  stick- 
ing to  the  surfaces  of  the  teeth,  gums  and  mucous  membrane 
of  the  mouth.  It  aids  in  forming  the  bolus  of  food  which 
makes  easy  the  act  of  swallowing.  A  deficiency  in  the  amount 
of  mucus  will  be  evidenced  by  difficulty  in  the  management 
of  food  in  the  process  of  mastication. 

The  water  of  the  saliva  acts  by  its  presence,  bathing  the 
surfaces  of  the  teeth,  this  action  being  promoted  by  the  move- 
ment of  the  muscles  of  the  cheeks  and  tongue,  by  which  it 
may  be  forced  through  the  interproximal  spaces  or  drawn 
through  by  the  action  of  suction.  The  habitual  use  of  this 
function  as  a  regular  exercise  in  performing  the  toilet  of  the 
teeth  may  be  of  marked  benefit. 

Thorough  mastication  also  influences  not  only  the  quantity 
and  quality  but  the  composition  of  the  saliva.  The  alkalinity 
of  the  saliva  is  dependent  upon  its  ash  content  and  with  an 
increased  flow  brought  about  by  the  stimulating  influence  of 
the  exercise  of  mastication  the  ash  content  is  increased  and 
consequently  the  alkalinity  proportionately  raised.  It  has 
been  shown  by  Pawlow  that  glandular  secretions  have  the 


32  HYGIENE:     DENTAL   AND   GENERAL 

property  of  adaptation ;  in  other  words  the  degree  of  alkalin- 
ity is  largely  influenced  by  the  character  of  the  food  to  be 
acted  upon.  In  periods  of  physiologic  rest  the  saliva  is 
weakly  alkaline  and  the  quantity  secreted  is  only  about  1  c.c. 
per  minute,  this  amount  being  greatly  increased  during  the 
period  of  active  functioning,  the  increase  depending  largely 
upon  the  nature  of  the  food  material.  It  is  interesting  to  note 
that  in  cases  of  dry  mouth  the  teeth  quickly  crumble  away. 
A  marked  increase  in  caries  is  usually  noted  in  any  pathologi- 
cal disturbance  of  glandular  activity.  Prinz  states  that  ' '  the 
quality  of  the  secreted  saliva  is  the  sole  factor  which  governs 
environmental  phenomena  concerning  tooth  decay." 


CHAPTER  II 

THE  HYGIENE  OF  NUTRITION 

The  process  of  keeping  the  body  in  a  properly  nourished 
condition  is  complex.  It  demands  the  consumption  of  suit- 
able foods  in  proper  quantities,  adequate  digestion,  the  trans- 
mission of  these  digested  foods  to  the  parts  of  the  body  where 
they  are  finally  used,  the  burning  of  the  fuel  foods,  the  re- 
building or  growth  of  the  tissue,  and  the  elimination  of  the 
waste  products  of  cell  activity.  The  Hygiene  of  Nutrition 
may  be  divided  into  the  problems  of  (1)  diet,  (2)  digestion, 
and  (3)  assimilation. 

1.  DIET 

Many  people  worrj^  about  how  to  get  the  foods  they  like, 
but  few  think  much  about  choosing  the  foods  which  the  body 
demands.  Indeed  if  one  led  an  active  and  normal  life  and 
could  choose  freely  among  the  foods  he  likes  he  could,  to  a 
large  extect,  rely  upon  his  natural  taste  to  select  the  proper 
diet.  To  select  a  diet  scientifically  or  to  know  where  the  un- 
scientific method'  breaks  down,  however,  we  must  understand 
the  nutritional  needs  of  the  body. 

These  dietary  needs  may  best  be  understood  by  studying 
the  products  of  digestion  which  finally  pass  through  the  walls 
of  the  stomach  and  intestines.  Were  you  able  to  accomplish 
the  gastronomic  feat  of  sampling  every  product  exhibited  at 
a  food  fair,  there  would  be  from  all  this  food  but  six  types 
of  digestive  products  finally  reaching  the  body  tissue.  To  ex- 
plain: if  we  regard  the  body  as  a  tube  within  a  tube,  as  we 
properly  may,  then  the  material  in  the  digestive  tract  is  not 
in  the  body  proper;  it  is  merely  in  contact  with  the  "inner 
skin"  and  may  only  reach  the  body  by  penetrating  tlie  intes- 
tinal wall.    Such  penetration  is  accomplished  by  only  six  kinds 

33 


34  HYGIENE:     DENTAL   AND   GENERAL 

of  substances :  (1)  water,  (2)  amino  acids,  (3)  simple  sugars, 
(4)  products  of  fat  digestion,  (5)  inorganic  salts,  and  (6) 
vitamines.  What  is  the  use  of  each  of  these  food  materials 
in  the  body?  Why  and  how  must  we  provide  a  diet  which 
will  insure  the  proper  amount  of  each  ? 

Water  makes  up  two-thirds  of  the  body  weight  and  in  ac- 
tive tissues  like  muscle  it  is  three-fourths  the  total  weight. 
Moreover,  the  body  has  a  liquid  carrier  system.  The  blood 
and  lymph,  which  are  mainly,  water,  carry  food  to  the  tissues 
and  remove  from  them  the  waste  products  of  combustion.  The 
chief  way  of  eliminating  waste  nitrogen  from  the  body  is  by 
means  of  the  water  passing  through  the  kidneys.  Every  in- 
dividual knows  that  in  making  thirst  more  painful  than 
hunger  nature  has  set  a  very  high  demand  upon  the  water 
diet. 

So  important  is  the  activity  of  water  that  we  might  almost 
speak  of  a  distinct  water  circulation  consisting  of  the  passage 
of  water  from  the  diet  into  the  body  and  its  elimination  from 
the  lungs  in  the  form  of  moisture,  from  the  skin  in  the  form  of 
sweat,  and  through  the  kidneys  in  the  form  of  urine.  The 
amount  of  water  excreted  in  these  ways  by  an  active  man  in 
the  course  of  a  day  amounts  to  over  two  quarts.  Yet  in  spite 
of  these  facts  a  deficiency  of  water  in  the  diet,  especially 
among  people  engaged  in  a  sedentary  occupation,  is  a  most 
common  and  serious  fault. 

Water  may  be  obtained  in  the  diet  in  a  variety  of  ways. 
The  greatest  quantity  of  course,  is  obtained  through  drinking 
water  and  other  beverages,  like  tea  and  coffee,  but  much  also  is 
obtained  from  the  solid  food.  This  is  notably  the  ease  with 
fruits  and  vegetables  many  of  which  contain  over  90  per  cent 
of  water.  Watermelon  is  98  per  cent  water.  Soup  and  broth 
are  also  sources  of  water  supply  in  the  diet.  The  amount  of 
water  necessary  for  proper  waste  elimination  and  for  feeding 
the  tissues  in  an  individual  of  average  weight  is  four  or  five 
pints  per  day.  Of  this,  at  least  six  glasses  should  be  drunk 
in  the  form  of  water  itself. 


HYGIENE   OP   NUTRITION  35 

Nitrog^enous  Foods. — The  chemically  simple  products  of 
protein  digestion  are  the  amino  acids.  They  are  the  sub- 
stances from  which  new  tissue  is  built  up  in  the  growing  body, 
and  from  which  worn-out  tissue  is  replaced  in  the  adult. 
These  compounds  are  sometimes  called  the  building  stones  of 
tissue  substance  because  they  recombine  on  the  other  side  of 
the  intestinal  wall  and  in  the  various  parts  of  the  body  to 
form  the  typical  body  proteins.  These  substances,  chemically 
of  simple  molecule,  contain  carbon  as  well  as  nitrogen  and 
may  therefore  undergo  partial  oxidation.  They  are  to  a  cer- 
tain extent  fuel  foods,  since  part  of  the  molecule  is  oxidized 
to  supply  heat  and  energy.  The  chemical  formula  of  one  of 
the  simplest  amino  acids,  glycocoll,  is  CH2NH2COOH.  Other 
amino  acids  are  of  larger  molecule. 

The  protein  foods  in  most  common  use  are  meat,  fish,  milk 
and  eggs,  although  much  nitrogen  is  to  be  found  in  the  lentils, 
peas  and  beans,  and  in  such  wheat  products  as  bread,  and 
macaroni.  Enough  of  this  type  of  food  is  required  to  supply 
nourishment  for  growing  or  wasted  tissue  but  it  has  usually 
been  found  that  where  man  is  free  to  choose  his  diet  to  a 
considerable  extent  there  is  an  excess  rather  than  a  deficiency 
of  protein.  Only  in  India  has  a  characteristic  protein  de- 
ficiency been  found  and  here  the  effects  among  the  members 
of  the  lower  classes,  where  meat  and  fish  are  rare  articles  of 
diet,  include  a  lessened  physical  vitality  and  a  dwarfed  stature. 
Where  protein  is  taken  in  excess  the  carbon  and  hydrogen 
portion  is  used  as  fuel  food  and  the  excess  of  nitrogen  is 
excreted  through  the  kidneys  in  the  form  of  urea.  The  office 
and  professional  worker  often  places  a  heavy  burden  on  the 
kidneys  by  making  them  excrete  a  large  amount  of  nitrogen 
in  only  a  small  amount  of  water. 

Carbohydrates. — The  carbohydrates  (sugars  and  starches) 
are  compounds  of  carbon,  hydrogen  and  oxygen  in  which 
hydrogen  and  oxygen  are  present  in  the  same  ratio  as  in 
water.  They  are  admirable  fuel  or  energy  producing  foods  be- 
cause when  they  are  oxidized  or  burned  in  the  body  they  are 


36  HYGIENE:     DENTAL   AND   GENERAL 

completely  broken  down  into  carbon  dioxide  and  water,  both 
of  which  are  easily  eliminated  waste  products, 

Digestion  reduces  all  sugars  and  starches  to  simple  sugars 
of  the  C^HigOg  type  such  as  dextrose  (glucose  or  grape  sugar) 
and  these  are  the  digestive  products  which  pass  through  the 
walls  of  the  alimentary  canal.  The  absorption  of  sugars  is 
rapid  and  begins  in  the  stomach.  For  this  reason  simple  sug- 
ars supply  the  body  with  fuel  very  promptly.  This  also  ex- 
plains why  eating  sweets  a  short  time  before  meals  takes  away 
the  appetite. 

Sugar  is  the  form  in  which  carbohydrate  is  transported 
and  used  in  the  body  while  starch  is  the  more  complex  storage 
form.  The  blood  usually  contains  from  0.06  to  0.1  per  cent 
sugar  and  a  reserve  supply  is  kept  in  the  liver  as  glycogen 
or  animal  starch.  The  body  is  free  to  draw  upon  this  reserve 
when  more  energy  is  needed  so  that  the  amount  of  sugar  in 
the  blood  may  be  increased  when  fear,  anger  or  other  emotions 
press  the  body  for  vigorous  action.  After  the  sugar  content 
of  the  blood  rises  to  0.2  or  0.3  per  cent  glycosuria  (the  pres- 
ence of  sugar  in  urine)  appears.  For  a  man  doing  physical 
work  especially  in  the  cold  where  heat  is  lost  rapidly  a  large 
carbohydrate  diet  is  essential  and  under  these  conditions  it  is 
natural  for  the  individual  to  increase  the  relative  amount  of 
carbohydrates  in  the  diet.  A  man  in  a  sedentary  occupation 
does  not  require  so  large  a  quantity  of  this  type  of  food. 

Fats. — The  third  type  of  food  passes  the  walls  of  the  ali- 
mentary canal  in  the  form  of  soap,  glycerine,  and  fatty  acids. 
The  fats  or  hydrocarbons  also  contain  the  elements  of  carbon, 
hydrogen,  and  oxygen  but  the  proportion  of  oxygen  is  less 
than  in  sugars  and  starches.  Consequently  they  may  be  re- 
garded as  fuel  foods  in  a  more  concentrated  form  since  the 
same  weight  requires  more  oxygen  for  combustion  and  there- 
fore is  of  greater  heat  value.  Fat  is  a  good  reserve  food 
since  large  quantities  may  be  stored  in  the  adipose  tissues. 
To  a  large  extent  it  is  interchangeable  in  the  diet  with  sugars 


HYGIENE   OF    NUTRITION  37 

and  starches.  Tlie  production  of  large  quantities  of  butter 
fat  by  the  cow,  which  subsists  upon  a  protein  and  carbohy- 
drate diet,  is  an  excellent  demonstration  of  the  ability  of  the 
animal  body  to  synthesize  fats  from  these  other  types  of  food. 
Inorganic  Salts. — The  fourth  group  of  body  foods  con- 
tains inorganic  salts  of  sodium,  calcium,  potassium,  sulphur, 
iron,  and  phosphorus.  The  salts  of  calcium  are  important  in 
forming  the  hard  structure  of  bone  and  the  dentin  of  the  teeth. 
The  chlorine  of  common  salt  is  used  in  the  production  of 
hydrochloric  acid  for  gastric  digestion.  Iron,  sulphur,  and 
phosphorus  are  important  constituents  of  the  more  vital  tis- 
sues. 

These  salts  are  obtained  in  organic  or  inorganic  form  but 
are  most  readily  usable  in  the  body  when  secured  as  organic 
salts  from  plant  and  animal  structures.  There  is  at  present 
a  tendency  among  physicians  to  prescribe  the  salts  needed  by 
the  body  in  the  organic  form  in  which  they  are  found  in  foods 
rather  than  in  the  inorganic  form  a«  they  are  frequently  com- 
bined in  drugs.  Most  proteins  are  found  associated  with 
some  of  these  minerals.  Lettuce  is  particularly  rich  in  potas- 
sium. Calcium  is  very  abundant  in  milk.  Phosphorus  is 
plentiful  in  meats  and  egg  yolk.  With  the  exception  of  iron 
the  salts  in  milk  (as  found  in  the  ash)  correspond  not  with 
those  in  the  blood  but  with  the  ash  obtained  from  the  whole 
young  animal.  Iron  is  very  plentiful  in  meat,  yolk  of  egg 
and  in  spinach,  apples  and  asparagus. 

Vitamines. — The  so-called  vitamines,  which  have  been 
classified  here  as  the  sixth  group  of  food  substances,  are  of 
a  chemical  composition  which  is  still  unlaiown.  It  is  evident 
however,  that  there  are  two  types  of  substances,  some  soluble 
in  water  and  some  soluble  in  fat,  which  arc  essential  to  the 
diet  in  preventing  the  onset  of  certain  so-called  dietary  dis- 
eases. They  are  found  in  the  husks  of  natural  grain,  in  vege- 
tative tissues  like  the  leaves  of  green  vegetables,  and  in  butter, 
olive  oil,  and  other  natural  fats. 


38  HYGIENE:     DEXTAL   AND    GENERAL 

Dietary  Diseases.- — A  dietary  deficiency  in  these  substances 
lias  been  establislied  as  a  cause  of  beri-beri,  rickets,  and  scurvy 
and  it  is  tbouglit  to  be  the  cause  of  pellagra. 

Beri-Beri  is  found  in  Asia  among  the  people  who  make  a 
large  part  of  their  diet  of  polished  rice.  It  is  characterized  by 
progressive  emaciation,  loss  of  weight  and  of  strength.  There 
is  neuritis,  the  inflammation  of  the  nerve  trunks  being  followed 
by  degeneration  resulting  in  prostration  and  frequently  in 
death.  This  disease  has  been  induced  experimentally  by  feed- 
ing birds  upon  polished  rice.  The  birds  showed  a  typical 
polyneuritis  with  inacti^dty,  loss  of  weight,  and  muscular 
contraction.  But  when  fed  with  an  aqueous  extract  of  rice 
bran  the  birds  immediately  recovered.  In  the  same  manner 
the  disease  among  human  subjects  has  been  stamped  out  by 
using  unpolished  rice  or  by  introducing  a  mixed  diet. 

Pellagra,  a  somewhat  similar  disease,  has  been  found  to  be 
most  common  in  countries  where  corn  is  the  chief  article  of 
diet  and  where  the  husk  and  germ  of  the  grain  are  removed 
before  grinding.  The  disfease  is  characterized  with  erjrthema, 
digestive  and  nervous  distui'bances.  Sometimes  cachexia, 
muscular  weakness  and  insanity  develop.  The  evidence  is 
not  as  clear  in  this  case  but  here  again  the  disease  seems  to 
be  produced  by  a  diet  of  the  pure  starch  of  a  cereal  food  to 
the  exclusion  of  the  leafy  and  vegetative  tissues  which  con- 
tain the  needed  vitamine. 

Scurvy,  which  is  produced  by  a  lack  of  fresh  foods  in  the 
diet,  was  a  common  disease  upon  ships  in  the  days  before  it 
was  possible  for  them  to  carry  a  larder  stocked  with  fresh, 
canned,  or  cold  storage  vegetables  and  meat.  It  has  now 
largely  disappeared.  The  introduction  of  the  potato  was  an 
important  factor  in  driving  the  scourge  from  Europe,  by  in- 
creasing the  quantity  of  fresh  vegetables  eaten.  InfantUe 
scurw  occasionally  results  from  the  exclusive  use  of  pasteur- 
ized milk.  The  feeding  of  a  small  quantity  of  orange  juice, 
however,  is  a  preventive  and  a  cure.  The  characteristics  of 
this  disease  are  weakness,  soreness  of  the  gums,  loosening  of 


HYGIENE    OF   XUTRITIOX  39 

the  teeth,  bleeding  from  the  mucous  membrane  and  friability 
of  the  bones. 

Rickets  is  a  dietary  disease  which  results  in  the  absence  of 
normal  growth  in  the  child  and  which  is  apparently  due  to 
the  lack  of  one  or  more  vitamines.  The  symptoms  include 
restlessness,  fever,  profuse  sweating,  emaciation  and  altera- 
tion in  the  growth  of  the  bones.  The  head  becomes  bulky, 
the  sides  of  the  thorax  flatten,  the  sternum  projects  and  fre- 
quently there  is  a  bending  of  the  spinal  column  and  long 
bones. 

Our  knowledge  of  these  subjects,  although  incomplet-e,  has 
given  an  added  importance  to  the  place  of  fresh  vegetables 
and  natural  fats  in  the  diet  of  children.  The  presence  of 
these  substances  is  essential  for  health  although  the  vitamines 
themselves  are  needed  only  in  minute  quantities. 

Balanced  Diet. — Proper  nutrition  not  only  demands  that 
these  six  kinds  of  foods  be  secured  but  that  they  be  secured 
in  proper  proportions.  This  proportion  may  be  judged 
roughly  from  the  composition  of  milk  which  is  the  perfect 
food  prepared  by  nature  for  young  infants.  Human  milk 
contains  approximately  2iy^%  protein,  33/2%  fat,  6145^  sugar 
and  0.25  %  inorganic  salt.  "We  find  therefore  that  water 
makes  86%  of  the  infant's  diet.  Vitamines  are  also  present 
in  mother's  milk  but  as  in  any  diet  in  analytically  negligible 
quantities. 

The  quantity  of  the  three  important  types  of  food  which 
are  necessary  for  a  normal  individual  has  usually  been  com- 
puted on  the  basis  of  the  number  of  calories  necessary  for 
the  individual.  A  calorie  is  the  amount  of  heat  required  to 
raise  a  kilogram  of  water  one  degree  centigrade.  It  is  pos- 
sible to  mcasui"e  the  energy  output  of  the  body  in  calories  and 
to  determine  the  heat  energy  in  the  same  way.  Each  gram 
of  protein,  fat,  and  carbohydrate  material  when  oxidized 
yields  respectively  4.1,  9.3  and  4.1  calories. 

It  is  found  that  the  energy  requirement  varies  according 
to  the  age  and  size  of  the  individual  and  the  amount  of  physi- 


40  HYGIENE:     DENTAL   AND    GENERAL 

eal  work  performed.  The  child  needs  more  protein  food  than 
the  adult  because  new  tissue  is  being  produced.  Murlin 
points  out  that  ice  cream  represents  the  proper  proportions 
for  adults  since  it  is  milk  plus  sugar  and  fat,  the  protein  being 
diluted.  1'he  child  also  needs  relatively  more  fuel  food  for 
the  work  done  because  the  small  body  has  more  surface  to 
the  unit  weight  and  the  amount  of  food  required  varies  more 


Fig.  9. — The  composition  of  cow's  milk.  The  bottles  are  arranged  from 
left  to  right  to  show  the  actual  amounts  of  water,  sugar,  fat,  protein  and  ash 
in  a  quart  of  milk. 


directly  with  the  surface  of  the  body  than  with  the  weight 
of  the  body. 

Men  doing  muscular  work  usually  secure  3,500  calories  or 
more  in  their  daily  ration.  People  of  sedentary  occupation 
find  something  less  tlian  2,500  to  be  sufficient.  The  following 
table  taken  from  Stiles'  Humam  Physiology  gives  a  suitable 
average  food  combination  for  the  sedentary  individual: 


HYGIENE    OF    NUTRITION 


41 


Proteiu 

Fat 

Carbohytlrate 

Total 


75  grams  or     300  calories 

50  grains  or     465  calories 

375  grams  or  1500  calories 


2265  calories 


Another  way  to  estimate  the  food  requirement  in  protein, 
carbohydrates,  and  fat  would  be  to  state  the  amount  of  some 
well-knowai  food  necessary  to  provide  a  sufficient  quantity  of 
each.     If  all  the  protein  in  the  day's  diet  were  to  be  secured 


Fig.  10. — Portions  of  different  foods  each  yielding  approximately  100  calories 
of  heat  energy.  They  include:  an  ordinary  serving  of  beans,  3  large  lumps  of 
sugar,  1  large  banana,  11  double  peanuts,  1  large  egg,  1  potato,  1  chop,  2  slices 
of  bread,  1  orange,  2  apples,  %  of -q^  glass  of  milk,  1  pat  of  butter,  and  an  average 
serving  of  oatmeal. 

from  lean  beefsteak,  all  the  fat  from  butter,  and  all  of  the 
carbohydrate  from  rice  the  individual  would  need  to  eat  ap- 
proximately the  following  quantities  of  these  foods  in  order 
to  secure  the  gram  or  caloric  rc(|uircment  mentioned  above: 

Beefsteak    %  lb.   (375  gr.) 

Butter    1^  lb.   (   59  gr.) 

Rice    1  lb.   (475  gr.) 


42  HYGIENE:     DENTAL   AND   GENERAL 

The  Varied  Diet. — The  whole  tendency  of  recent  dietary 
study  has  been  to  show  that  variety  in  diet  is  necessary.  A 
variety  of  proteins  is  desirable  because  each  protein  is  made 
up  of  a  different  combination  of  amino  acids,  which  we 
have  called  the  building  blocks;  and  in  order  to  be  sure  to 
include  in  the  food  all  of  the  amino  acids  needed  by  the  body 
many  different  proteins  should  be  eaten.  Again  we  have  seen 
that  fresh  vegetables,  leafy  tissues,  meats  and  natural  fats 
contain  "vitamine"  substances  which  are  little  known  chem- 
ically but  which  are  necessary  for  a  proper  balancing  of  the 
diet. 

Furthermore,  man  must  choose  a  reasonable  amount  of  hard 
foods  in  order  to  exercise  the  jaw  and  preserve  the  teeth.  A 
certain  amount  of  bulk  must  also  be  secured  to  furnish  a  stim- 
ulus for  peristalsis  in  the  intestines  and  maintain  the  normal 
activity  of  the  bowels.  This  is  secured  by  eating  fruit,  vege- 
tables and  other  bulky  foods  poor  in  nutritive  value. 

2.  DIGESTION 

Good  digestion  is  something  more  than  the  mere  swallowing 
of  the  proper  number  of  grams  of  the  various  kinds  of  food 
each  day.  To  get  the  best  results  the  food  must  be  appetizing, 
the  person  must  be  in  the  proper  mental  state,  the  food  must 
be  eaten  in  suitable  fashion,  and  bodily  activities  must  not 
seriously  interfere  with  digestion. 

Digestion  and  the  Emotions. — The  recent  work  of  Dr.  Can- 
non upon  the  emotions  {Bodily  Changes  in  Pain,  Hunger, 
Fear  and  Rage,  by  Walter  D.  Cannon;  D.  Appleton  &  Co., 
1915)  has  shown  us  clearly  the  importance  of  proper  psychic 
conditions  in  normal  digestion.  Nowhere  else  is  there  such  a 
good  statement  of  the  facts  at  hand.  Conunenting  upon  the 
previous  work  of  Pawlow  with  dogs  Cannon  says: 

By  the  use  of  careful  surgical  methods  he  was  able  to  make  a  side 
pouch  of  a  part  of  the  stomach,  the  cavity  of  which  was  wholly  separate 
from  the  main  cavity  in  which  the  food  was  received.  This  pouch  was 
supplied  in  a  normal  manner  with  nerves  and  blood  vessels  and  as  it 


HYGIENE   OF    NUTRITION  43 

opened  to  the  surface  of  the  body,  the  amount  and  character  of  the 
gastric  juice  secreted  by  it  under  various  conditions  could  be  accurately 
determined.  *  *  *  In  some  of  the  animals  thus  operated  upon  an 
opening  was  also  made  in  the  esophagus  so  that  when  the  food  was 
swallowed,  it  did  not  pass  to  the  stomach  but  dropped  out  on  the  way. 
All  the  pleasures  of  eating  were  thus  experienced,  and  there  was  no 
necessity  of  stopping  because  of  a  sense  of  fullness.  This  process  was 
called  "sham  feeding."  The  well-being  of  these  animals  was  carefully 
attended  to,  they  lived  the  normal  life  of  dogs,  and  in  the  course  of 
months  and  years  became  the  pets  of  the  laboratory. 

By  means  of  sham  feeding  Pawlow  showed  that  the  chewing  and 
swallowing  of  food  which  the  dogs  relished  resulted,  after  a  delay  of 
about  five  minutes,  in  a  flow  of  natural  gastric  juice  from  the  side  pouch 
of  the  stomach — a  floAv  which  persisted  as  long  as  the  dog  chewed  and 
swallowed  the  food,  and  continued  for  some  time  after  eating  ceased. 
Evidently  the  presence  of  food  in  the  stomach  is  not  a  prime  condition 
for  gastric  secretion.  And  since  the  floAV  occurred  only  when  the  dogs 
had  an  appetite,  and  the  material  presented  to  them  was  agreeable,  the 
conclusion  was  justified  that  this  was  a  true  psychic  secretion. 

Other  experiments  upon  dogs  have  shown  that  merely  the 
sight  or  smell  of  a  favorite  food  will  start  the  pouring  out  of 
the  gastric  juice.  Analogy  teaches  us  that  good  cookery  not 
only  makes  our  mouth  water  but  it  makes  our  stomachs  water 
as  well.  This  initial  psychic  secretion  of  gastric  juice  is  im- 
portant because  the  continuance  of  its  flow  during  digestion 
is  brought  about  by  the  reaction  of  its  acid  or  digestive  pro- 
ducts upon  the  mucous  membrane  of  the  duodenum. 

The  saliva  produced  when  the  mouth  waters  not  only  starts 
the  digestion  of  starches  but  it  also  assists  in  enabling  us  to 
taste  our  food,  for  materials  are  tasted  only  when  they  are 
dissolved. 

To  quote  further  from  Dr.  Cannon's  excellent  description: 

The  conditions  favorable  to  proper  digestion  arc  wholly  abolished 
when  unpleasant  feelings  such  as  vexation  and  worry,  or  great  emotion 
such  as  anger  and  fear,  are  allowed  to  prevail.  This  fact,  so  far  as  the 
salivary  secretion  is  concerned,  has  long  been  known.  The  dry  mouth 
of  the  anxious  person  called  upon  to  speak  in  public  is  a  common  in- 
stance ;  and  the  ' '  ordeal  of  rice, ' '  as  employed  in  India,  Avas  a  practical 
utilization  of  tlie  knowledge  that  excitement  is  capable  of  inhibiting  the 
salivary  floAV.     Wlien  several  persons  Avere  suspected  of  crime,  the  con- 


44  HYGIENE:     DENTAL   AND   GENERAL 

secrated  rice  was  given  to  them  all  to  cliew,  and  after  a  short  time  it 
was  spit  out  upon  the  leaf  of  the  sacred  fig  tree.  If  anyone  ejected 
it  dry,  that  was  taken  as  proof  that  fear  of  being  discovered  had 
stopped  the  secretion,  and  consequently  he  was  adjudged  guilty. 

What  has  long  been  recognized  as  true  of  the  secretion  of  saliva  has 
been  proved  true  also  of  the  secretion  of  gastric  juice.  For  example, 
Hornborg  was  able  to  confirm  in  his  little  patient  with  a  gastric  fistula 
the  observation  by  Pawlow  that  when  hunger  is  present  the  mere  seeing 
of  food  results  in  a  flow  of  gastric  juice.  Hornborg  explained  the 
difference  between  his  and  Pawlow 's  results  by  the  different  ways  in 
which  the  boy  and  the  dogs  faced  the  situation.  Wlien  food  was  shown, 
but  withheld,  the  hungry  dogs  were  all  eagerness  to  secure  it,  and  the 
juice  very  soon  began  to  flow.  The  boy,  on  the  contrary,  became  vexed 
when  he  could  not  eat  at  once,  and  began  to  cry;  then  no  secretion  ap- 
peared. Bogen  also  has  reported  the  instance  of  a  child  with  closed 
esophagus  and  gastric  fistula,  who  sometimes  fell  into  such  a  passion  in 
consequence  of  vain  hoping  for  food  that  the  giving  of  food,  after  the 
child  was  calmed,  was  not  followed  by  any  flow  of  the  secretion.     *     *     * 

The  studies  of  Bickel  and  Sasaki  confirm  and  define  more  precisely  this 
inhibitory  effect  of  strong  emotion  on  gastric  secretion.  They  observed 
the  inhibition  on  a  dog  with  an  esophageal  fistula,  and  with  a  side  pouch 
of  the  stomach,  which,  as  in  Pawlow 's  experiments,  opened  only  to  the 
exterior.  In  this  dog  Bickel  and  Sasaki  noted,  as  Pawlow  had,  that 
sham  feeding  was  attended  by  a  copious  flow  of  gastric  juice,  a  true 
psychic  secretion,  resulting  from  the  pleasurable  taste  of  the  food.  In 
a  typical  instance  the  sham  feeding  lasted  five  minutes,  and  the  secre- 
tion continued  for  twenty  minutes,  during  which  time  66.7  cubic  centi- 
meters of  pure  gastric  juice  were  produced. 

On  another  day  a  cat  was  brought  into  the  presence  of  the  dog, 
whereupon  the  dog  flew  into  a  great  fury.  The  cat  was  soon  removed, 
and  the  dog  pacified.  Now  the  dog  was  again  given  the  sham  feeding 
for  five  minutes.  In  spite  of  the  fact  that  the  animal  was  hungry  and 
ate  eagerly,  there  was  no  secretion  worthy  of  mention.  During  a  period 
of  twenty  minutes,  corresponding  to  the  previous  observation,  only  9 
cubic  centimeters  of  acid  fluid  were  produced,  and  this  was  rich  in 
mucus.     *     *     * 

On  another  occasion  Bickel  and  Sasaki  started  a  gastric  secretion 
in  the  dog  by  sham  feeding,  and  when  the  flow  of  gastric  juice  had 
reached  a  certain  height,  the  dog  was  infuriated  for  five  minutes  by 
the  presence  of  a  cat.  During  the  next  fifteen  minutes  there  appeared 
only  a  few  drops  of  a  very  mucous  secretion.     *     *     * 

Eecently  Oechsler  has  reported  that  in  such  psychic  disturbances,  as 
were  shown  by  Bickel  and  Sasaki  to  be  accompanied  by  suppressed  se- 


HYGIENE   OP   NUTRITION  45 

crction  of  the  gastric  juice,  the  secretion  of  pancreatic  juice  may  be 
stopped,  and  the  flow  of  bile  definitely  checked.  All  the  means  of  bring- 
ing about  chemical  changes  in  the  food  may  be  thus  temporarily  abol- 
ished. 

Dr.  Cannon  describes  most  interestingly  his  own  experi- 
ments which  show  that  the  excitement  in  pain,  fear  and  rage 
also  prevent  the  normal  contractions  of  the  stomach  and  in- 
testines. 

Even  indications  of  slight  anxiety  may  be  attended  by  complete  ab- 
sence of  the  churning  waves.  In  a  vigorous  young  male  cat  I  have 
watched  the  stomach  for  more  than  an  hour  by  means  of  Eoentgen  rays, 
and  during  that  time  not  the  slightest  beginning  of  peristaltic  activity 
appeared;  yet  the  only  visible  indication  of  excitement  in  the  animal  was 
a  continued  quick  twitching  of  the  tail  to  and  fro. 

Physicians  who  treat  great  numbers  of  digestive  disorders 
frequently  receive  a  clinical  history  of  indigestion  with  symp- 
toms of  heaviness  in  the  stomach  after  eating,  as  though  the 
food  failed  to  pass  on  to  the  intestines.  Such  a  case  exhibits 
an  increasingly  aggravated  condition.  This  type  of  nervous 
or  emotional  indigestion  in  specific  cases  has  been  shown  to 
be  definitely  related  to  unfavorable  mental  states.  The  ac- 
companying diagram  shows  the  way  in  which  the  autonomic 
nervous  system  reaches  and  affects  the  various  parts  of  the 
body. 

It  should  be  added  here  that  the  secretion  of  adrenalin  and 
the  increase  of  the  sugar  content  of  the  blood  are  important 
and  complicating  factors.  Not. only  is  digestion  completely 
inhibited  by  the  stronger  emotions  but  the  blood  and  muscles 
are  supplied  with  more  fuel  and  the  circulatory  and  nerv- 
ous systems  are  toned  up  to  enable  man  to  exert  his  utmost 
physical  strength  as  he  was  usually  called  upon  to  do  during 
his  more  primitive  existence  and  during  the  long  period  of 
evolution. 

The  Hygiene  of  the  Emotions. — Certain  conclusions  inev- 
itably follow.  Digestion  ensues  much  more  readily  if  the  food 
eaten  is  appealing  in  sight,  odor  and  taste.  Among  people 
who,  because  of  illness  or  for  some  other  reason  have  a  dainty 


46 


HYGIENE:     DENTAL.   AND   GENERAL 


Fig.  11 — Diagram  showing  the  most  important  distributions  of  the  Autonomic 
JNervous  System.  One-half  of  the  brain  and  spinal  cord  is  represented  at  the 
left.  The  preganglionic  fibers  of  the  Autonomic  Nervous  System  are  in  solid 
hnes;  the  postganglionic  in  dash  lines.  The  cranial,  cervical,  dorsal,  lumbar, 
and  sacral  divisions  of  the  nervous  system  are  indicated  by  the  letters  Cr,  Ce, 
p,  Lu,  and  Sa,  respectively.  The  organs  indicated  as  affected  by  the  emotions 
include  the  lachrymal  glands,  the  pupils  of  the  eyes,  the  salivary  glands,  heart, 
hair,  superficial  arteries,  sweat  glands,  adrenal  bodies,  stomach,  intestines,  colon, 
bladder,   and   genitals.      (After  Cannon.) 


HYGIENE   OF    NUTRITION  47 

appetite  special  care  in  these  particulars  is  very  important. 
It  is  also  clear  that  the  forced  feeding  of  children,  the  un- 
necessary punishment  of  children  at  the  table,  and  feeding 
immediately  after  the  child  has  been  in  a  passion  are  all  un- 
hygienic. Amon^  adults  it  is  equally  important  that  the 
meal  should  be  pleasant  and  free  from  anxiety,  worry  and  ill- 
feeling.  Otherwise  a  vicious  cycle  will  be  set  up  and  the 
man  who  begins  by  worrying  at  his  meals  or  thinking  in- 
tensely upon  the  problems  of  his  work  will  set  up  a  mild  in- 
digestion which  will  in  turn  lower  his  efficiency,  aggravate 
his  work  by  depleting  his  physical  condition  and  initiate  him 
into  the  unstable  and  unenviable  fraternity  of  neurasthenics. 

"^ Enjoy  your  food"  is  an  excellent  maxim.  Enjoy  your 
meal,  the  surroundings,  the  company  and  the  food.  Choose 
food  which  you  will  enjoy  eating  and  eat  slowly.  If  food  is 
eaten  under  proper  conditions  it  is  much  more  likely  to  be 
eaten  properly. 

Mastication. — The  digestion  of  starches  and  sugars  and 
the  preparation  of  these  substances  for  absorption  is  begun 
in  the  mouth.  If  these  foods  are  swallowed  without  proper 
chewing  and  the  addition  of  saliva  their  normal  digestion  is 
impossible. 

Important  beginnings  of  protein  digestion  take  place  in 
the  stomach  by  the  action  of  the  peptic  secretion  from  the 
walls  of  the  stomach  and  these  are  carried  further  by  the 
action  of  the  pancreatic  juice  and  other  fluids.  These  fluids 
must  act  upon  the  exposed  surfaces  of  foods  and  therefore  if 
a  piece  of  meat  the  size  of  a  marble  is  cut  into  particles  the 
size  of  coai'se  sand  by  proper  chewing,  the  surface  area  avail- 
able for  digestive  action  is  increased  many  fold.  The  prin- 
ciple adopted  by  Horace  Fletcher,  who  selected  foods  which 
appealed  to  his  appetite  and  chewed  all  food  till  it  was  prac- 
tically liquid  in  the  mouth,  is  sound  but  more  difficult  of  suc- 
cessful practice  for  the  poor  and  busy  man  than  it  was  for 
Mr.  Fletcher. 


48  HYGIENE:     DENTAL   AND   GENERAL 

Water  With  Meals. — There  has  been  much  discussion  about 
the  advisability  of  drinking  quantities  of  water  with  the 
meals.  There  seems  to  be  no  reason  why  water  taken  with  the 
meals  should  be  injurious  unless  it  is  used  to  wash  down  dry 
food  in  order  to  save  the  individual  the  trouble  of  chewing 
or  unless  it  is  taken  at  a  low  temperature  and  in  such  quan- 
tities as  to  cool  the  stomach  and  slow  up  the  action  of  the 
secretive  tissues  of  the  stomach  wall. 

Rest  After  Eating. — In  experiments  recorded  above  Paw- 
low  shows  that  the  secretion  of  gastric  juice  lasted  for  twenty 
minutes  after  the  end  of  a  five  minute  period  of  sham  feeding. 
Bickel  has  also  shown,  in  the  case  of  a  girl  with  a  closed 
esophagus  and  gastric  fistula,  that  gastric  secretion  continued 
active  for  some  time  after  eating  even  when  no  food  had 
entered  the  stomach.  We  have  also  seen  that  the  effects  of 
the  unpleasant  emotions  and  mental  states  are  sufficient  to 
inhibit  the  secretion  of  digestive  juices  after  the  process  is 
once  started.  For  these  reasons  and  because  of  the  with- 
drawal of  blood  from  the  digestive  tract  to  the  muscular 
organs  in  the  case  of  hard  manual  labor  we  may  conclude  that 
an  after-lunch  rest  period,  postponing  for  at  least  one-half 
hour  the  return  to  active  labor,  is  highly  desirable. 

3.  ASSIMILATION 

Assimilation  Defined. — The  processes  of  nutrition  which 
take  place  after  the  food  has  been  absorbed  by  the  walls  of 
the  digestive  tract  and  taken  into  the  circulation  are  chiefly 
the  functions  of  the  absorption  and  combustion  of  the  food 
material  in  the  tissues  and  the  elimination  of  waste  from  the 
body.  These  processes  include  the  use  of  the  gaseous  food, 
oxygen,  and  the  elimination  of  the  chief  end  products  of  com- 
bustion, water,  carbon  dioxide  and  urea.  Nitrogen  is  elimin- 
ated through  the  kidneys,  in  the  form  of  urea,  carbon  dioxide 
through  the  lungs,  and  water  through  the  lungs,  kidneys  and 
skin. 


HYGIENE   OF    NUTRITION  -  49 

Oxidation. — Apparently  assimilation  is  not  impaired  by 
a  lack  of  oxygen  due  to  poor  ventilation.  As  we  shall  see  in 
describing  ventilation,  the  injurious  effects  of  poor  air  are 
not  due  to  the  chemical  content  of  the  air  but  to  an  entirely 
different  set  of  factors.  The  supplying  to  the  tissues  of  this 
all  important  gaseous  food  depends  much  more  upon  proper 
breathing  and  suitable  exercise.  These  matters  will  be  con- 
sidered in  more  detail  under  the  hygiene  of  action. 

Eliminating'  the  Body  Wastes. — The  elimination  of  urea 
is  made  easier  by  limiting  the  protein  diet  so  as  to  avoid  an 
excess  of  nitrogen  for  elimination  by  the  kidneys  and  by 
drinking  large  quantities  of  water  in  order  to  reduce  the  con- 
centration of  the  urine.  It  has  been  shown  that  the  action 
of  the  kidney  in  withdrawing  the  salts  of  urea  from  the  blood 
and  combining  them  in  a  much  more  concentrated  form  in 
the  urine  involves  definite  energy  consumption. 

The  evacuation  of  the  bowels  is  mainly  the  elimination 
from  the  body  of  substances  which  have  never  passed  through 
the  walls  of  the  alimentary  canal  since  the  secretions  which 
are  thrown  into  the  digestive  tract  constitute  but  a  small 
part  of  the  feces.  But  we  should  not  neglect  to  reaffirm  the 
importance  of  so  regulating  the  diet  and  the  habits  that  de- 
fecation may  be  regular  in  order  that  the  material  in  the 
rectum  and  lower  bowel  may  not  become  inspissated  and  ab- 
sorbed to  such  an  extent  that  the  blood  is  loaded  with  these 
poisonous  waste  proteins  and  the  vitality  of  the  individual 
temporarily  impaired. 

Autointoxication. — We  have  seen  that  the  emotions  may 
so  interfere  with  digestion  that  the  process  is  not  properly 
commenced  or  if  underway  it  is  brought  to  an  abrupt  stop. 
When  this  occurs  food  may  remain  in  the  stomach  for  many 
hours  instead  of  being  passed  on  to  the  intestine.  The  bac- 
teria, which  are  always  present  in  the  digestive  tract  in  count- 
less numbers,  are  especially  active  when  digestion  and  normal 
absorption  is  delayed  so  that  the  fermentations  which  they 
set  up  in  the  intestine  produce  gas  and  cause  pain.     Under 


50  -  HYGIENE:     DENTAL   AND   GENERAL 

normal  conditions  tlie  nitrogenous  food  is  largely  absorbed 
before  the  material  reaches  the  colon  but  if  digestion  has  not 
been  sufficiently  completed  these  proteins  do  reach  the  large 
intestines  and  undergo  putrefaction  with  the  consequent  pro- 
duction of  poison  which  will  be  absorbed  into  the  blood  and 
produce  the  ill  effects  of  autointoxication. 

The  signs  of  beginning  or  transient  autointoxication  are 
drowsiness,  inertia,  headache  and  a  feeling  of  fatigue.  If  it 
is  long  persistent  nervous  depression,  hardening  of  the  ar- 

Nii^tritional 
Disturbance 


Jnhappy  Mental  State  Delayed  Absorption. 


Increased  Bacterial  Action. 


Absorption  of  abnormal  products 
of  bacterial  ax:tion. 

'■  Fig.   12. — The  worry-autointoxication   cycle. 

teries,  anemia,  and  arthritis  may  result.  The  body  will  re- 
cover from  a  single  attack  of  autointoxication  but  it  may  be 
readily  seen  that  long  continued  grief  or  anxiety  may  produce 
a  chronic  condition  which  in  turn  would  increase  the  nervous 
trouble  setting  up  a  vicious  cycle. 

Overeating  as  well  as  the  emotions  will  cause  autointoxi- 
cation and  it  is  possible  that  the  slightly  excessive  consump- 
tion of  food  may  in  the  long  run  produce  injurious  effects. 
Fortunately  for  the  individual  greatly  overloading  the  stom- 


HYGIENE   OF    NTTTRITION  51 

ach  is  likely  to  be  followed  by  a  mild  diarrhea.  In  the  case 
of  autointoxication  the  occasional  use  of  *a  cathartic  is  bene- 
ficial but  it  should  not  be  used  too  often.  Moderation  and 
temperance  in  eating  especially  in  the  eating  of  protein  foods 
is  most  important.  The  drinking  of  sour  milk  or  the  regular 
ingestion  of  lactic  acid  bacteria  is  a  measure  aimed  to  prevent 
the  putrefaction  associated  with  autointoxication  by  substi- 
tuting lactic  acid  fermentation  as  the  dominant  type  of  bac- 
terial action  in  the  alimentary  canal. 

Constipation  or  the  sIoav  movement  of  food  along  the  in- 
testinal track  may  or  may  not  be  associated  with  autointoxi- 
cation. Its  seriousness  is  overemphasized  in  the  ever  present 
advertisements  for  cathartics,  but  the  condition  is  harmful 
and  should  be  avoided  by  the  use  of  plenty  of  water,  by  eating 
"roughage"  such  as  fruit  and  vegetables  and  by  suitable 
exercises.  A  habit  of  at  least  one  movement  a  day  at  a 
regular  time  should  be  established.  The. habitual  use  of  ca- 
thartics or  enemas  should  not  be  encouraged. 

Food  Poisoning. — The  newspapers  frequently  recount 
cases  of  "ptomaine  poisoning"  in  which- persons  suffer  from 
extreme  pain,  diarrhea,  and  frequently  from  forcible  vomit- 
ing, coupled  with  a  high  fever  and  extreme  prostration.  Pto- 
maines are  supposed  to  be  poisonous  substances  produced  by 
the  bacterial  decomposition  of  nitrogenous  food  under  certain 
conditions.  It  is  lately  much  less  common  to  hear  of  ptomaine 
poisoning  and  many  cases  which  have  been  so  reported  have 
been  found  upon  investigation  to  be  due  to  bacterial  infection. 
In  fact  the  existence  of  specific  ptomaines  is  in  question.  Re- 
cent experiments  upon  the  quality  of  canned  foods  have  com- 
pletely failed  to  disclose  the  presence  of  ptomaines  or  other 
poisons. 

Certain  people  are  poisoned  by  particular  foods  such  as 
pears,  eggs,  lobsters,  etc.  This  type  of  poisoning  is  hard  to 
understand  but  it  may  be  a  type  of  anaphylatic  reaction  as 
suggested  in  the  chapter  on  Immunity. 


52  HYGIENE:     DENTAL   AND   GENERAL 

Obesity. — The  tendency  to  become  overweight  is  no  doubt 
constitutional  although  of  course  it  is  true  that  adipose  tissue 
ean  only  be  acquired  by  the  continued  consumption  of  more 
fuel  than  is  used  by  the  body. 

There  are  two  ways  to  combat  overweight,  by  reducing  the 
amount  of  food  or  by  increasing  the  oxidation.  When  we  are 
not  eating  we  are  losing  weight  at  the  rate  of  about  one  ounce 
an  hour.  Fasting  will  reduce  weight  but  it  is  extremely  un- 
pleasant. Sometimes  drugs  are  given  which  destroy  one's 
appetite  but  they  too  are  likely  to  be  unpleasant  and  to  injure 
digestion.  The  oxidation  of  food  may  be  increased  by  ex- 
ercise but,  unfortunately  for  the  person  who  is  trying  to  re- 
duce, exercise  is  followed  by  an  increased  appetite  and  a 
greater  consumption  of  food. 

The  use  of  a  diet  high  in  protein  is  sometimes  recommended. 
This  decreases  the  amount  of  food  eaten  because  protein 
quickly  satisfies  hunger  and  also  accelerates  the  process  of 
oxidation.  This  procedure  always  places  too  heavy  a  burden 
upon  the  kidneys ;  and  perhaps  a  better  and  more  consistent 
plan  is  to  substitute,  in  so  far  as  possible,  coarse  and  bulky 
foods  like  fruit  and  vegetables  for  the  fuel  foods  like  sugar, 
starches  and  fats.  In  this  way  hunger  can  be  satisfied  with- 
out taking  too  much  nutritive  material. 

Under-Eating-. — Common  and  bothersome  as  are  the  prob- 
lems of  overweight  cases  of  under-eating  are  perhaps  more 
serious  and  more  frequent.  Many  people  suffer  the  loss  of 
physical  and  mental  vigor  because  through  carelessness  in 
their  eating  habits  or  lack  of  means,  they  fail  to  secure  the 
food  that  they  should  have.  Women,  particularly,  often  fail 
to  secure  suitable  and  nourishing  food  because  of  the  expense 
or  because  of  the  trouble  of  preparing  food  for  themselves 
when  they  are  alone. 

Such  a  person  is  in  many  respects  the  exact  opposite  of  the 
individual  who  is  overweight.  The  underfed  person  drags 
himself  about — underweight,  pale,  sensitive  to  cold,  morose, 
querulous,  and  pessimistic.     He  sleeps  lightly  and  works  with- 


HYGIENE   OF   NUTRITION  53 

out  enthusiasm  and  without  surplus  energy.  The  overfed 
person  is  perhaps  not  very  diligent  but  he  is  cheerful,  opti- 
mistic, of  ruddy  countenance,  and  a  heavy  sleeper.  To  secure 
the  golden  mean  in  diet  is  greatly  to  be  desired  but  perhaps  it 
is  better  to  err  slightly  on  the  side  of  plenty. 

CONCLUSIONS 

Many  factors  are  involved  in  the  proper  regulation  of  the 
diet.  The  protein  must  be  applied  in  suitable  quantity  and 
variety.  The  quantity  of  the  fuel  foods  must  be  adjusted  to 
the  kind  of  work  being  done.  Plenty  of  water  is  essential. 
The  necessary  inorganic  salts  must  be  secured  from  various 
sources  and  vitamine  substances  must  be  provided.  The  emo- 
tions must  not  be  allowed  to  impair  the  digestion  and  proper 
habits  of  eating  should  be  acquired. 

Every  person  should  study  himself  and  learn  what  foods 
best  agree  with  him.  He  should  experiment  to  find  the  best 
arrangement  for  hours  and  types  of  meals.  In  general  men 
doing  mental  work  find  that  they  can  do  best  when  the  break- 
fast and  lunch  are  not  too  heavy  and  the  hearty  meal  is  eaten 
at  night.  Lunch  particularly  should  be  light,  if  work  is  to 
be  done  early  in  the  afternoon.  Many  but  not  all  people 
work  best  on  a  light  breakfast.  But  in  all  these  things  per- 
sonal habits,  bodily  constitution,  and  daily  schedule  are  im- 
portant and  although  there  are  some  general  rules  every  per- 
son must  learn  what  best  agrees  with  him. 


CHAPTER  III 

THE  HYGIENE  OF  ACTION 

Two  Kinds  of  Bodily  Activity. — Independent  activity  of 
the  organism  begins  with  birth  and  ends  only  with  death. 
Even  the  person  who  avoids  physical  evercise  carries  on  a 
variety  of  muscular  activities  including  the  beating  of  the 
heart,  breathing,  and  the  functions  of  walking,  riding,  sitting, 
standing,  eating,  gesturing,  talking,  etc.  Some  of  these  activi- 
ties are  involuntary  and  others  are  so  simple  as  not  to  require 
careful  attention,  but  in  all  these  activities  and  in  a  con- 
trasted group  of  activities  which  we  may  term  active  physical 
exercise,  there  arise  certain  problems  of  hygiene. 

EXERCISE 

Voluntary  muscular  activity  or  exercise  will  be  first  con- 
sidered. The  professional  man  or  the  individual  engaged  in 
a  sedentary  occupation  Avill  do  well  to  give  careful  attention 
to  the  beneficial  effects  of  regular  and  proper  exercise  and  to 
the  dangers  incident  to  its  neglect.  Exercise  is  more  essential 
to  his  happiness  than  mental  development  is  to  the  happiness 
of  a  man  employed  in  active  physical  labor. 

It  is  a  pernicious  fallacy  to  regard  healthful  and  vigorous 
exercise  as  an  unnecessary  burden  in  the  day's  work  merely 
because  the  changed  living  conditions  since  the  days  of  our 
forefathers  have  rendered  mental  activity  the  usual,  and  phys- 
ical activity  tlie  unusual  mode  of  life  for  the  professional, 
business  and  clerical  classes.  Especially  among  the  intellec- 
tually inclined  there  is  danger  that  the  desire  for  a  good  phys- 
ical condition  of  the  body  may  stop  with  the  envy  of  those 
who  possess  such  a  body  or  with  an  attempt  to  secure  the  same 
stimulation  in  another  way  or  by  an  easier  road,  in  using  mas- 

54 


HYGIENE    OF   ACTION  55 

sage,  alcoholic  stimulants,  drugs  and  patent  medicines,  instead 
of  learning  the  real  delight  and  joy  of  a  proper  physical 
condition  resulting  from  well-directed  exercise. 

What  Exercise  Does  for  the  Body. — Briefly,  what  are  the 
real  and  actual  effects  of  regular  physical  exercises  upon  the 
body?  In  the  first  place  it  is  a  most  important  stimulus  to 
the  circulation  of  the  blood  and  the  lymph.  The  movement 
of  the  muscles  and  other  organs  exerts  a  massaging  action  on 
these  two  streams  in  the  capillaries  and  lymph  spaces ;  and  the 
increased  respiration  exerts  a  suction  upon  the  venous  blood 
into  the  great  veins  near  the  heart  by  the  same  bellows-like 
action  witli  which  air  is  drawn  into  the  lungs.  This  increased 
breathing  is  also  important  to  the  lungs  themselves  in  filling 
air  spaces  which  under  normal  conditions  may  not  be  iised, 
and  particularly  in  inflating  the  apical  regions  of  the  lungs. 

The  increased  bodily  activity  increases  the  oxidation  going 
on  in  the  body.  The  extent  of  this  action  is  shown  by  the 
fact  that  the  output  of  carbon  dioxide  is  increased  from  three 
to  ten  times  by  muscular  activity  whereas  the  digestive  process 
only  increases  its  output  one-fifth.  This  carbon  dioxide  is 
thrown  off  through  the  lungs.  AYater  is  another  waste  pro- 
duct and  the  skin  is  cleared  by  the  generous  excretion  of  the 
sweat  glands  and  the  consequent  softening  of  the  horny 
layers. 

The  most  generally  obvious  aspect  of  exercise  is  the  build- 
ing up  of  the  general  muscular  system  which  constitutes  two- 
thirds  of  the  bulk  and  weight  of  the  body.  Muscle  fibrils 
increase  in  size  when  used  but  when  unused  they  decrease 
until  hardly  more  than  the  connective  tissue  remains  of  what 
should  be  a  strong  and  vigorous  muscle.  Nor  is  this  unim- 
portant for  the  man  of  sedentary  occupation,  because  for 
everyone  there  are  emergencies  which  must  be  met  by  unusual 
physical  energy.  Eunning  for  a  street  car,  running  upstairs, 
or  sudden  emergencies  which  occur  in  the  professional  activity 
of  the  dentist  or  physician,  require  physical  energy  and  often 
considerable  muscular  strength.    This  need  of  reserve  strength 


56  HYGIENE:     DENTAL   AND   GENERAL 

is  especially  important  in  the  case  of  the  heart  which  like 
the  skeletal  muscles  is  built  up  and  strengthened  by  proper 
physical  exercise.  In  the  emergencies  cited  above  and  in 
certain  diseases  like  pneumonia  it  is  primarily  important  that 
the  heart  is  sufficiently  strong  to  withstand  the  strain.  In 
fact,  in  disease  the  strength  of  the  heart  often  determines  the 
question  of  life  or  death. 

But  the  other  internal  organs  also  gain  vastly  from  physi- 
cal exercise.  The  viscera  are  relieved  from  serious  internal 
congestion  which  is  likely  to  take  place  in  the  body  of  a 
sedentary  individual  and  which  predisposes  the  internal 
organs  to  diseased  condition.  The  stagnation  of  the  blood 
and  lymph  in  the  large  vessels  running  from  the  digestive 
organs  to  the  heart  interferes  with  digestion,  circulation,  and 
the  sense  of  physical  well  being.  Digestion  itself  is  aided  by 
the  increased  peristalsis  produced  by  the  churning  activities 
of  these  organs  and  by  the  increased  use  of  the  abdominal 
muscles. 

To  anyone  who  has  learned  to  enjoy  physical  exercise  it 
is  not  necessary  to  say  that  the  general  toning  up  of  the  bodily 
activities,  the  improvement  of  the  circulation  and  all  the  at- 
tendant changes  mentioned  above,  produce  a  beneficial  effect 
on  the  mental  tone.  Of  equal  importance  is  the  effect  upon 
the  heat -regulating  mechanism.  Muscular  activity  opens  the 
small  blood  vessels  of  the  muscles  and  the  region  near  the 
skin  and  contracts  the  blood  vessels  of  the  internal  viscera. 
It  is  upon  our  ability  to  make  these  changes  that  we  rely  in 
large  part  for  our  bodily  adjustments  to  changes  of  temper- 
ature. A  trained  and  adaptive  heat-regulating  mechanism 
is  therefore  essentially  important  to  the  general  health. 

In  summ.arizing  the  foregoing  we  may  list  the  beneficial 
effects  of  muscular  exercises  as  (1)  an  aid  to  circulation, 
(2)  an  aid  to  oxidation,  (3)  an  aid  in  the  elimination  of 
waste,  (4)  clearing  the  skin,  (5)  strengthening  the  muscular 
system,  (6)  aiding  digestion,  (7)  improving  the  mental  tone, 
(8)  relieving  internal  congestion,  (9)  strengthening  and  en- 


HYGIENE    OF   ACTION  "  57 

larging  the  lungs,  (10)  strengthening  the  heart,  and  (11)  im- 
proving the  heat  regulating  mechanism. 

Types  of  Physical  Exercise. — The  type  of  physical  exer- 
cise which  one  may  take  depends  upon  his  physical  fitness,  age 
and  inclination.  It  is  far  better  to  build  a  good  body  in 
youth  and  to  maintain  its  efficiency  throughout  life,  but  it  is 
never  too  late  too  begin  bodily  improvement  provided  this  is 
done  in  a  sane  and  proper  manner.  To  allow  a  horse  to  re- 
main in  the  stable  for  weeks  then  drive  it  a  hundred  miles  in 
a  day  would  spoil  the  animal;  yet  many  people  expect  the 
human  mechanism  to  accomplish  similar  feats,  in  rare  and  im- 
moderate exercise.  Some  who  rarely  exercise  go  to  excess  be- 
cause when  the  opportunity  to  exercise  offers  itself  there  is  a 
joyous  outlet  of  pent-up  energy  and  the  individual  does  not 
realize  ( at  least  until  he  tries  to  get  out  of  bed  the  next  morn- 
ing) that  an  unused  muscular  system  has  its  limitations. 
Others  overdo  because  they  have  once  been  athletic  and  do 
not  realize  that  absence  from  regular  exercise  has  depleted 
their  powers  of  endurance. 

The  first  requisites  of  the  most  helpful  exercise  are  that  it 
should  be  regular,  enjoyable,  and  adapted  to  the  individual. 
The  person  who  religiously  resolves  to  attend  the  gymnasium 
at  least  three  times  a  week  finds  that  after  the  second  or  third 
week  it  begins  to  pall  on  him.  If  he  is  taking  routine  exer- 
cises, he  goes  through  a  definite  set  of  mental  processes.  As 
the  hour  approaches  for  him  to  enter  the  gymnasium  he  has 
a  feeling  of  dislike  for  the  task  and  is  sure  that  he  would 
prefer  continuing  his  office  activities.  Through  moral  force 
however  he  persuades  himself  to  go,  and  after  completing  his 
exercise  and  being  refreshed  by  a  shower  bath  he  feels  so 
invigorated  that  he  firmly  resolves  to  enter  the  gymnasium 
six  times  a  week  instead  of  three.  Yet  the  same  compulsion 
must  be  exercised  the  very  next  day  if  he  is  to  resume  his 
exercises. 

The  strengthening  of  the  physical  and  mental  fiber  will 
certainly  repay  this  individual  if  he  persists  in  the  regular 


58  HYGIENE:     DENTAL   AND   GENERAL 

routine  of  exercise.  Gymnasia  are  invaluable  assets  in  the 
life  of  the  city.  If,  however,  the  exercise  can  be  varied  so 
that  the  man  takes  a  delight  and  looks  forward  to  the  time 
when  he  will  have  an  opportunity  to  exercise,  much  is  accom- 
plished. With  some  individuals  the  innovation  of  athletic 
games  accomplishes  this  result.  Such  a  man  takes  a  keen  joy 
in  a  contest ;  in  making  himself  expert  and  proficient  in  a 
particular  way.  Still  another  type  of  mind  dislikes  any  ac- 
tivity which  is  not  productive.  Hunting,  fishing,  exploring, 
training  horses,  gardening,  carpentering,  etc.,  all  appeal  to 
such  a  man  and  fortunate  is  he  who  can  elect  his  ideal  exer- 
cise from  this  group.  These  activities,  however,  are  not  al- 
v/ays  available  to  the  occupant  of  a  five  room  flat;  so  perhaps 
we  should  say  most  fortunate  is  the  man  who  can  become  fond 
of  any  of  the  types  of  physical  exercises  mentioned. 

Rhythm  in  Exercise. — More  should  be  said  about  the  na- 
ture of  the  exercise  itself.  It  should  involve  rhythmic  and 
not  continued  muscular  contraction.  A  type  of  exercise  like 
tennis,  baseball,  or  football  is  a  much  more  general  and  in- 
vigorating bodily  exercise  than  the  mere  lifting  of  heavy 
v/eights.  The  exercise  should  be  such  that  free  play  is  granted 
to  the  various  parts  of  the  body.  The  lungs  should  be  free 
to  expand  to  their  fullest  extent,  and  the  movements  of  the 
trunk  should  be  free  and  easy.  That  exercise  is  most  helpful 
which  is  sufficiently  varied  to  call  into  use  a  great  number  of 
the  muscles  of  the  body.  Above  all  things  the  exercise  should 
be  reasonably  vigorous. 

Walking'. — Walking,  which  is  an  excellent  exercise  and 
available  to  everyone,  should  never  be  confused  with  loitering 
or  strolling.  Fast  walking  in  the  open,  especially  in  the 
country,  is  invigorating,  restful  and  has  the  added  advantage 
of  making  the  man  interested  in  his  surroundings  and  in  the 
wonders  of  the  natural  world  which  he  was  meant  to  enjoy. 
Mere  strolling  even  though  it  be  in  the  open  is  not  proper 
exercise  and  is  tiring  rather  than  restful.  Air  is  good  and 
essential  but  the  mere  breathing  of  fresh  air  cannot  take  the 
place  of  physical  exercise. 


HYGIENE   OF   ACTION  59 

ORDINARY  BODY  ACTIVITIES 

The  other  phase  of  the  Hygiene  of  Action,  which  we  men- 
tioned in  the  beginning  of  this  discussion,  concerns  the  proper 
use  of  the  body  in  the  ordinary  affairs  and  conduct  of  life. 
This  involves  also  the  matter  of  figure,  bodily  shape,  and 
physical  force;  because  these  depend  upon  the  proper  coord- 
ination and  balance  of  the  muscular  system. 

Figure. — Good  figure  and  proper  carriage  are  important 
not  only  in  the  personal  appearance  of  the  individual,  directly 
affecting  his  personality  and  the  estimate  set  upon  his  ability 
by  the  casual  observer;  but  they  are  also  important  to  health 
as  deformities  injure  and  restrict  adjacent  organs.  The  body 
is  largely  made  up  of  opposing  sets  of  muscles  which  tend  to 
move  the  various  parts  in  the  opposite  directions  like  the  flexor 
and  extensor  muscles  of  the  lower  leg  or  arm.  Similar  sets  of 
muscles  alter  the  position  of  the  neck,  the  chest,  the  back  and 
the  jaw.  We  shall  see  how  the  improper  use  of  particular 
muscles  may  distort  the  normal  figure  of  the  body.  This  is 
particularly  noticeable  respecting  the  shoulders,  the  neck,  the 
back,  the  abdomen  and  the  feet. 

Round  Shoulders. — Round  shoulders  have  become  so  com- 
mon among  large  groups  of  sedentary  workers  that  there  is 
danger  that  we  may  conclude  that  they  are  normal.  The 
round-shouldered  individual  himself  is  likely  to  feel  that  he 
has  assumed  an  abnormal  position  when  he  straightens  up. 
When  straight  he  looks  unnatural  merely  because  he  is  not  in 
his  habitual  or  customary  position.  It  is  only  when  we  look 
at  the  erect  posture  of  a  child  of  three  or  four  years  or  the 
bearing  of  the  well  trained  soldier  that  we  realize  how  odious 
is  round-slioulderedness  compared  with  the  natural  contour. 

This  condition  is  brought  about  by  drawing  the  shoulders 
forward  through  the  contraction  of  the  muscles  of  the  chest 
and  the  disuse  of  the  muscles  of  the  back  so  that  finally  the 
muscles  become  set  in  this  position  with  the  chest  muscles 
contracted  and  the  back  muscles  relaxed  leaving  the  shoulders 
in  a  forward  position,  cramping  the  upper  part  of  the  chest 


60 


HYGIENE:     DENTAL   AND   GENERAL 


and  limiting  tlie  breathing.  This  deformity  is  brought  about 
by  a  careless  attitude  at  the  desk  or  by  leaning  forward  over 
one's  work,  and  the  individual  must  develop  consciousness  of 
physical  position  in  order  to  avoid  incorrect  posture.  Cor- 
rective exercises,  in  consciously  throwing  the  shoulders  back 
with  the  arms  widely  extended  to  one  side  or  in  raising  the 
arms  above  the  head  at  the  same  time  drawing  a  deep  breath 
and  dropping  the  arms  slowlj^  during  the  period  of  exhaling, 
keeping  the  hands  well  to  the  rear,  are  effective  in  correct- 
ing this  condition. 


'  Fig.  13. — Good  (left)  and  bad  (right)  postures.  The  main  lines  of  the  body 
are  shown  in  diagram  and  it  is  easy  to  see  that  the  position  at  the  right  would 
be  much  more   tiring.      (Burgerstein.) 


Carrying  the  Head  Forward. — ^Another  malady  which  often 

accompanies  round  shoulders  is  the  fault  of  carrying  the 
head  too  far  forward.  The  neck  becomes  accustomed  to 
an  abnormal  position  and  is  no  longer  erect.  This  again  is 
due  to  the  weakness  of  the  muscles  w^hich  hold  the  head 
back,  and  the  set  contraction  of  the  muscles  which  pull 
the  head  forward.  One  of  the  first  corrective  exercises  for 
both  these  conditions  is  that  of  flattening  the  back  against 


HYGIENE   OF   ACTION 


61 


a  straight,  perpendicular  wall.  The  individual  backs  up  to 
a  door  or  wall  and  places  himself  in  such  a  position  that  the 
calves  of  the  legs,  the  hips,  the  shoulders,  and  the  back  of 
the  head  lie  flatly  against  the  w^all.  This  is  approximately 
the  normal  posture  and  if  a  man  walks  away  in  this  position 


TRACINGS  MADi:  DURING  EXAMINATION   OF   700   HARVARD 
FRESHMEN 


Group  A— 7.5%  Group  B— 12.5%  Group  C— 55%  Group  D— 25% 
Fig.   14. — Posture  chart  showing  the  result  of  the  examination  of  Harvard  Freshmen. 

Group  A. — Good  mechanical  use  of  the  human  body.  1.  Head  straight  above 
chest,  hips  and  feet.  2.  Chest  up  and  forward.  3.  Abdomen  in  or  flat.  4.  Back 
usual  curves  not  exaggerated. 

Group  B. — Fairly  good  mechanical  use  of  the  human  body.  (Note  changes  from 
Group  A.)  1.  Head  too  far  forward.  2.  Chest  not  so  well  up  or  forward.  3.  Ab- 
domen very  little  changed.     4.  Back  very  little  changed. 

Group  C. — Bad  mechanical  use  of  the  body.  (Note  changes  from  Group  A.) 
1.  Head  forward  of  chest.  2.  Chest  flat.  3.  Abdomen  relaxed  and  forward. 
4.  Back  curves  are  exaggerated. 

Group  D.— Very  bad  mechanical  use  of  the  body.  (Note  changes  from  Group 
A.)  1.  Head  still  farther  forward.  2.  Chest  still  flatter  and  farther  back.  3.  Ab- 
domen completely  relaxed.  "Slouchy."  4.  Back  all  curves  exaggerated  to  the 
extreme.     (Lee.) 

and  maintains  it  for  some  time,  repeating  the  exercise  ev- 
ery morning  he  will  gradually  accustom  himself  to  the 
proper  position  of  the  head  and  shoulders  and  this  position 
will  become  the  natural  one.  Another  way  to  exercise  the 
muscles  at  the  back  of  the  neck  is  to  clasp  the  hands  be- 


62  HYGIENE:     DENTAL   AND    GENERAL 

hind  the  head  and  force  the  head  back  against  their  pres- 
sure. 

Spinal  Curvatures. — Another  common  fault  in  posture  is 
the  abnormal  curving  of  the  spine  either  laterally  or  back- 
ward at  the  region  of  the  thorax  or  forward  at  the  region 
of  the  abdomen.  This  latter  is  often  associated  with  pro- 
trusion of  the  abdomen  by  increase  in  fat  and  the  relaxing 
of  the  ventral  abdominal  muscles. 

The  curvature  of  the  back  may  be  prevented  in  large  part 
by  the  exercise  of  trying  to  make  oneself  as  tall  as  possible, 
holding  the  back  straight  and  rising  on  the  toes  with  arms 
extended  over  the  head,  stretching  the  arms  and  body.  The 
objectional  "pot  belly"  condition  may  be  successfully  pre- 
vented and  largely  overcome  by  such  exercises  as  lying  flat 
on  the  floor  or  bed  with  arms  folded  and  raising  the  feet  and 
head  alternately.  Lateral  curvatures  arise  from  sitting  in  a 
leaning  position  and  are  most  common  in  children  who  sit 
improperly  at  school. 

Deformities  of  the  Feet. — ^Less  conspicuous  but  none  the 
less  important  deformities  are  those  which  are  found  in  the 
feet.  In  selecting  shoes  man  seems  to  conclude  that  nature 
made  a  mistake  in  making  the  foot  broad  at  the  toe  and  he 
endeavors  to  make  it  over  into  a  wedge-shaped  organ ;  while 
woman  tries  to  improve  upon  nature  by  walking  upon  the 
toes  and  elevating  the  heels  instead  of  walking  upon  the 
flat  of  the  foot.  If  you  will  observe  an  infant  or  small 
child  you  will  find  that  the  toes  are  flexible  and  move  side- 
ways and  backwards  and  forwards  to  a  great  degree.  When 
a  child  walks  the  toes  "dig  into  the  ground."  Held  in  by 
the  shoes  in  later  life  this  early  flexibility  and  the  original 
shape  of  the  foot  are  largely  lost.  Especially  in  people  who, 
like  dentists,  are  required  to  remain  on  their  feet  for  many 
hours  a  day,  do  we  find  painful  and  harmful  foot  conditions. 

There  is  a  natural  arch  running  from  the  heel  to  the  ball 
of  the  foot  and  a  small  reverse  arch  from  the  toes  to  the 
top  of  the  instep.     These  arches  are  held  in  position  by  a 


HYGIENE    OF    ACTION  63 

complex  group  of  muscles.  If  these  muscles  are  not  used 
or  if  they  are  so  bound  up  that  they  are  not  given  proper 
free  play,  the  weight  of  the  body,  centering  in  front  of  the 
heel,  tends  to  break  down  the  arches  and  produce  a  condition 
known  as  flat  foot.  This  defect  will  be  rather  prevalent  un- 
til common  sense  rules  fashion  and  people  demand  proper 
shoes. 

To  take  proper  care  of  the  feet  the  shoe  must  be  as  wide 
as  the  foot,  the  heels  must  be  low  and  broad,  the  toes  and 
uppers  of  the  shoes  must  be  flexible,  there  must  be  room 
for  activity  at  the  toes  of  the  boot  and  the  foot  must  be  held 
in  such  a  position  when  walking  that  it  is  carried  straight 
ahead.  In  a  normal  foot  the  line  drawn  through  the  long 
axis  of  the  great  toe  should  also  pass  through  the  heel. 

The  foot  must  be  given  proper  exercise  to  strengthen  the 
muscles  of  the  ball  of  the  foot  and  the  arch.  Dig  the  toes 
into  the  ground  when  you  walk,  practice  the  ordinary  gym- 
nastic exercise  of  "heels  raised,  knees  bend,"  thus  calling 
the  muscles  of  the  foot  into  play.  Do  not  wear  the  shoe 
or  the  garter  so  tight  as  to  cause  congestion  of  the  blood  in 
the  foot.  All  of  these  things  are  very  important  in  securing 
fair  treatment  for  one  of  the  most  abused  members  of  the 
body. 

The  public  must  learn  that  from  the  aesthetic  standpoint 
a  small  foot  with  a  pointed  toe  and  high  heel  is  not  the  ideal 
foot. 

Such  is  not  the  foot  of  the  Apollo  Belvedere  nor  that  of  the  Venus  of 
Milo.  It  is  simply  a  deformity,  belonijiM";  :':i  the  same  category  with  the 
constricted  Avaist,  and  far  more  harmful  to  its  possessor  than  the  ear 
or  nose  ornaments  of  the  Hottentot.  No  liygienic  lesson  is  more  im- 
portant than  that  clothing-  should  fit  the  body  and  not  the  body  the 
clothing. — Scdgunclc. 

Ocular  Hygiene. — The  proper  use  of  the  eyes  and  ears 
forms  an  important  part  in  the  ordinary  activities  of  life  al- 
though somewhat  removed  from  the  subject  of  muscular  ac- 
tion.   Both  of  these  complicated  sense  organs  require  expert 


64  HYGIENE:     DENTAL   AND   GENERAL 

attention  if  there  is  anything  seriously  wrong.  Their  im- 
portance and  their  complexity  both  demand  this.  We  should 
remember  that  headaches  and  even  the  nausea  accompanying 
the  so-called  ''sick  headache"  may  be  produced  by  defects 
in  the  eyes  which  are  perhaps  more  often  congenitally  ab- 
normal than  any  other  organ. 

We  can  do  much  to  take  care  of  the  eyes  by  being  careful 
to  use  a  steady  and  not  a  flickering  light  when  we  read, 
by  choosing  paper  which  is  dull  and  not  of  a  glossy  finish, 
and  by  avoiding  in  so  far  as  possible,  the  use  of  any  print  so 
fine  that  it  is  necessary  to  hold  the  book  less  than  eighteen 
inches  from  the  eyes.  Occasionally  the  eyes  may  be  rested 
from  the  work  immediately  at  hand  by  changing  the  focus, 
looking  out  of  the  window,  and  focusing  the  eyes  upon  some 
distant  object.  This  is  merely  an  act  of  muscular  relaxation 
to  prevent  the  strain  which  would  otherwise  be  caused  by 
the  continual  focusing  of  the  eyes  upon  near  objects. 

Breathing. — By  the  process  of  breathing  the  blood  acquires 
oxygen  and  discharges  carbon  dioxide  and  the  body  throws 
off  moisture.  Nearly  all  of  the  carbon  dioxide  produced  in 
the  body  is  discharged  through  the  lungs  and  about  one 
pint  of  water  a  day  is  thrown  off  in  this  manner. 

The  red  blood  corpuscles  are  like  tiny  boats  hauling  oxy- 
gen from  the  lungs  to  the  tissues  and  exchanging  it  there 
for  carbon  dioxide  which  is  brought  back  to  the  lungs  and 
discharged  into  the  air  which  is  being  exhaled.  But  the 
cargo  of  these  boats  is  never  limited  entirely  either  to  CO2 
or  oxygen  for  both  gases  are  found  in  considerable  quantity 
in  either  the  arterial  or  the  venous  blood.  It  is  as  though 
our  "ships"  were  always  carrying  a  certain  amount  of 
each  as  ballast  and  emptying  only  a  part  of  their  compart- 
ments at  the  lungs  and  in  the  tissues.  One  hundred  volumes 
of  arterial  blood  contain  about  20  volumes  of  oxygen  and  38 
volumes  of  carbon  dioxide.  One  hundred  volumes  of  venous 
blood  contain  about  12  volumes  of  oxygen  and  45  volumes 
of  carbon  dioxide.     It  seems  that  there  is  always  enough 


HYGIENE    OF   ACTION  65 

of  proper  "cargo"  at  either  ''loading  point"  for  the  boat 
to  take  on  its  usual  load;  for  a  person  can  breathe  without 
discomfort  in  air  which  has  so  much  carbon  dioxide  that  a 
match  will  not  burn  in  it.  On  the  other  hand  the  rate  of 
oxidation  is  not  increased  when  a  person  breathes  pure 
oxygen.  Only  when  the  blood  has  fallen  below  standard 
in  disease  or  during  extreme  exertion  does  the  breathing  of 
pure  oxygen  have  any  advantage  over  the  breathing  of 
normal  air.  Here  it  helps  to  restore  the  standard  of  the 
blood. 

The  rate  of  breathing  is  not  affected  by  the  chemical  com- 
position of  the  air.  It  is  controlled  by  the  concentration  of 
carbon  dioxide  in  the  blood  through  its  effect  upon  a  spe- 
cial regulating  nerve  center.  Exercise,  therefore,  naturally 
increases  the  rate  of  respiration  and  this  is  the  best  way  to 
take  breathing  exercises. 

When  one  practices  forced  hreathing  he  is  likely  to  be- 
come dizzy  or  faint.  The  concentration  of  carbon  dioxide  in 
the  blood  is  reduced  below  the  point  which  should  be  main- 
tained as  a  stimulus  to  the  nervous  tissues.  The  most  imme- 
diate effect  is  upon  the  breathing  center  which  ceases  to  send 
out  the  necessary  stimuli  with  the  result  that  breathing  is 
stopped  or  slowed  down  until  sufficient  carbon  dioxide  has  ac- 
cumulated again.  Breathing  sufficiently  forced  to  produce 
dizziness  is  not  to  be  recommended.  It  is  Avell  to  breathe 
deeply  at  a  normal  rate,  however,  and  to  keep  the  chest 
expanded.  Deep  breathing  increases  the  capacity  and  vigor 
of  the  lungs  and  by  keeping  the  chest  Avell  expanded  the 
figure  is  improved,  the  heart  and  great  blood  vessels  are 
given  sufficient  room  and  the  diaphragm  is  allowed  a  free- 
dom of  action  which  is  highly  beneficial  to  the  internal 
organs. 

Bathingf. — The  first  function  of  bathing  is  to  keep  the 
skin  and  body  clean.  Otherwise  the  skin  glands  will  leave 
upon  the  surface  solid  substances  which  are  odorous  and  pu- 
trescible.     Cleanliness  not  only  keeps  the  skin  healthy  and 


66  HYGIENE:     DENTAL    AND    GENERAL 

vigorous ;  it  avoids  the  presence  of  dirt  which  is  a  possible  car- 
rier of  disease;  and  it  is  directly  related  to  the  self-respect 
of  the  individual. 

Perhaps  something  should  be  said  of  the  temperature  at 
which  baths  are  taken.  The  hot  hath  opens  the  pores  of  the 
skin  by  stimulating  the  activity  of  the  skin  glands.  It  fol- 
lows that  its  too  frequent  use  may  make  the  skin,  dry  by  re- 
moving the  oil  and  that  such  a  bath  leaves  the  individual 
highly  susceptible  to  exposure  to  cold.  It  should  not  be 
taken  too  often  or  before  going  out  into  the  open  air.  On 
the  other  hand,  a  hot  bath  or  foot  bath  before  going  to  bed 
helps  to  break  a  cold  by  bringing  the  blood  to  the  skin  and 
stimulating  the  circulation. 

If  taken  under  proper  conditions  the  cold  hath  is  fol- 
lowed by  a  warm  glow  as  the  heat-regulating  mechanism 
sends  the  blood  back  to  the  skin  to  neutralize  the  effect  of 
cold.  Such  baths  should  not  be  prolonged  over  a  minute 
and  should  be  taken  in  a  warm  room  when  the  skin  is  warm 
and  followed  by  a  good  rub.  They  should  not  be  taken 
within  one  hour  after  eating.  Some  find  that  cold  baths 
use  too  much  of  their  .energy.  B.y  disturbing  the  circula- 
tion of  the  internal  organs  they  maj"  rarely  result  in  con- 
stipation when  taken  regularly  each  morning. 

The  indifferent  hath  in  which  the  water  is  from  80  to  90  de- 
grees F.  lacks  both  depressing  and  stimulating  effects  and 
is  a  good  type  of  daily  bath  for  many  people  particularly 
those  A\dio  are  not  the  most  robust. 

Clothing. — If  the  daily  activities  are  to  be  performed 
with  comfort  suitable  clothing  is  necessary.  The  great  essen- 
tial in  securing  proper  clothing  is  to  provide  constant  ven- 
tilation for  the  body,  that  is,  a  continual  change  of  the 
"aerial  blanket."  The  type  of  clothing  depends  upon  the 
nature  of  the  fiber  from  which  the  clothing  is  made.  The 
mesh  of  the  round  woolen  fiber  makes  a  cloth  in  which  there 
are  innumerable  spaces  filled  with  air  and  therefore  the 
clothing  is  warm  and  not  a  good  conductor  of  heat  or  cold. 


HYGIENE    OP    ACTION 


67 


On  the  other  hand,  cotton  fabrics  are  made  from  flat  fibers 
readily  pressed  together  in  such  a  way  that  air  is  excluded 
from  the  meshes.  The  cotton  cloth  therefore,  allows  a  ready 
exchange  of  air  about  the  body  and  is  a  good  conductor  of 
heat.  Eubber  fabrics  are  not  porous  at  all  and  allow  no 
passage  of  air  from  one  side  to  another. 

Woolen  clothing  is  much  warmer  than  cotton  and  is  suit- 
able for  the  person  who  is  doing  out-of-door  Avork  or  riding 
in  the  open  during  winter  weather.  It  is  an  undesirable  fab- 
ric for  underclothing  for  people  who  are  working  indoors 
in  the  city.  Our  offices  and  shops  are  more  likely  to  be  too 
warm  than  too  cold  and  the  perspiration  of  the  body  in 
such  a  temperature  is  not  readily  evaporated  through 
woolen.  It  is  absorbed  by  a  thick  woolen  garment  and  the 
body  does  not  secure  the  relief  it  should  have.  At  the  end  of 
four  or  five  hours  in  the  office,  however,  the  garment  is  sat- 
urated with  perspiration  and  all  of  the  spaces  formerly 
filled  Avith  air  have  become  filled  with  water  so  that  the 
underclothing  is  now  a  very  good  conductor  of  heat  and 
when  the- person  emerges  into  the  cold  air  the  Avater  in  the 
garment  cools  and  the  person  is  chilled  in  his  cold  damp 
clothes.  For  the  man  in  town,  therefore,  it  is  much  better 
to  wear  light  underclothing  and  compensate  for  this  by 
putting  on  heavy  outer  garments  when  emerging  into  cold 
air.  If  he  is  careful  to  Avalk  briskly  and  keep  up  his  bodily 
activity  while  out  of  doors  or  Availing  for  a  car  he  has  another 
means  of  increasing  his  bodily  heat  by  increasing  the  oxida- 
tion process  in  the  tissues. 


CHAPTER  IV 

THE  HYGIENE  OF  THE  CENTRAL  NERVOUS  SYSTEM 

The  proper  care  and  conservation  of  that  exceedingly  com- 
plex machine,  the  central  nervous  system,  upon  which  depend 
the  sensations  of  consciousness  and  the  efficiency  of  our  men- 
tal and  physical  activities,  is  highly  important. 

Function. — Through  physiology  and  anatomy  we  early 
learned  of  it  as  a  telephone-like  system  of  communication  hav- 
ing the  central  station  in  the  brain,  from  which  orders  are 
constantly  being  sent  during  our  waking  moments,  and  having 
substations  in  our  reflex  and  sympathetic  nervous  systems 
which  are  capable  of  handling  minor  emergencies  flashed  in 
as  impressions  from  those  parts  of  the  body  connected  with 
each  substation.  The  higher  centers  are  subject  to  a  contin- 
ual bombardment  of  impulses  and  stimuli  from  the  sense- 
organs. 

This  is  a  system  composed  of  living  substance  which  de- 
mands rest  between  periods  of  great  activity  and  like  other 
living  tissues  it  increases,  through  use,  its  facility  in  the  work 
it  has  to  do.  But  if  it  is  overused  or  al)used  it  becomes 
hypersensitive.  Stimuli  which  ought  not  to  go  beyond  the 
substations  are  flashed  through  to  the  head  station  and  trifles 
interfere  with  important  activities.  The  person  is  irritable 
and  the  system  is  unable  to  carry  out  its  normal  functions. 

Without  taking  time  to  review  the  structure  or  function  of 
the  system  in  detail  we  shall  consider  the  hygiene  of  the 
nervous  system  flrst  in  health  and  later  in  disease.  It  is 
common  experience  that  the  nervous  system  becomes  tired 
at  the  end  of  the  day's  work.  We  know  that  the  activities 
of  the  normal  life  place  demands  upon  it  which  must  be  com- 
pensated by  periods  of  rest.  Our  interest  here  concerns  the 
efficient  functioning  of  the  nervous  system  and  the  important 

68 


HYGIENE   OF    CENTRAL    NERVOUS    SYSTEM  69 

ways  in  which  rest  and  efficiency  are  secured  by  the  normal 
and  healthy  individual. 

Concentration. — Perhaps  the  most  important  character- 
istic of  the  efficient  nervous  system  is  the  power  of  concen- 
tration upon  the  task  at  hand.  This  is  expressed  in  another 
way  as  the  power  of  inhibiting  undesirable  stimuli.  It  is 
equally  valuable  in  work  and  in  rest.  In  work  the  individual 
inhibits  from  the  center  of  consciousness  those  thoughts  which 
are  not  germane  to  the  subject  in  hand  and  also  those  stimuli 
which  arise  from  the  surroundings,  trying  to  make  their  way 
to  the  center  of  consciousness  through  the  portals  of  sight, 
hearing,  touch,  and  perhaps  taste  and  smell.  In  the  efficient 
mind  such  stimuli  and  the  inconsequential  thoughts  which 
arise  from  their  associated  ideas  are  rigidly  excluded  from  the 
conscious  thought. 

Eecreation  has  the  reverse  process  and  the  individual  se- 
verely forbids  thoughts  and  worries  of  his  work  to  crowd  in 
upon  the  enjoyment  of  the  pleasures  which  he  has  allowed 
himself.  For  those  people  who,  like  great  executives,  are 
obliged  to  shoulder  heavy  responsibilities  and  are  weighed 
down  with  numerous  cares,  the  power  of  complete  relaxation 
may  be  a  saving  grace.  The  criticism  which  has  sometimes 
been  placed  upon  Lincoln  and  other  men  of  this  type  for  brief 
periods  of  light-heartedness  in  the  midst  of  great  problems  is 
entirely  unjust  and  unreasonable. 

The  power  of  concentration  is  so  intimately  linked  with 

efficiency  and  personal  success  that  one  may  well  ask  how  it 

may  be  secured  or  improved.     Perhaps  the  most  valuable  aid 

s  good  health  for  with  it  the  body  is  freed  from  minor  pains, 

rritations  and  morbid  sensations  which  are  constantly  break- 

ng  into  the  train  of  thought  of  the  physically  unfit,  opening 

the  way  for  other  distracting  influences. 

Fondness  for  one's  work  is  another  important  factor,  since 
the  work  itself  is  making  a  constant  appeal  to  the  mentality 
and  the  volition.  That  is  why  there  is  a  unity  between  the 
things  people  like  to  do  and  the  things  they  do  well.    The  ar- 


70  HYGIENE:     DENTAL    AND    GENERAL 

rangement  of  one's  workshop  or  desk  in  such  a  way  that  but 
one  thing  at  a  time  is  before  the  worker  is  important,  and 
often  it  is  of  material  assistance  to  occupy  the  hands  with  a 
pencil  in  making  notes  or  sketches  or  with  models,  apparatus 
or  instruments  in  studying  technique.  A  man  will  do  well  to 
study  the  lighting,  furnishings  and  equipment  of  the  work 
place  to  eliminate  distracting  stiinuli  such  as  might  arise  from 
the  reflected  light  of  a  glossy  page,  uncomfortable  chairs  or 
confusion  of  material. 

Habit. — Habit  is  another  important  factor  in  the  conserva- 
tion of  the  nervous  system.  The  processes  of  eating  and 
dressing  are  exceedingly  difficult  for  the  young  child,  but 
by  the  adult  they  can  be  accomplished  while  the  mind  is  de- 
voted to  a  more  pleasant  plane  of  thought  than  the  necessary 
mechanical  operations  which  are  being  performed.  In  the 
same  way  many  activities  connected  with  the  daily  work  may 
be  relegated  to  the  realm  of  habit  and  thus  the  energy  of  the 
nervous  system  may  be  spared.  Energy-saving  habits  are 
highly  desirable  but  there  are  some  dangers  here.  It  goes 
without  saying  that  good  and  not  bad,  hygienic  and  not  un- 
hygienic habits  should  be  formed. 

But  apart  from  this  psychologists  have  pointed  out  a  group 
of  so-called  indifferent  habits  like  the  continual  use  of  par- 
ticular words  and  phrases,  the  lack  of  reasonable  variety  in 
dress  and  recreation.  They  have  pointed  out  that  old  age  is 
a  fixity  of  the  nervous  system  which  such  long-continued 
habits  have  limited  to  particular  channels  of  thought  and 
action.  If  this  is  true  it  is  possible  to  postpone  old  age  by 
occasionally  breaking  up  these  habits  in  a  determined  fashion 
and  freeing  the  mind  from  those  ruts. 

Sleep. — To  the  normal  person  sleep  is  the  great  refreshing 
agent  for  the  nervous  system.  The  nature  of  this  invaluable 
process  still  awaits  complete  explanation.  There  are  two 
other  types  of  unconsciousness ;  namely,  intoxication  by  drugs, 
in  Avhich  sensations  are  blocked  from  reaching  the  central 
nervous  system,  and  fainting,  where  consciousness  is  lost  be- 


HYGIENE    OF    CENTRAL    NERVOUS    SYSTEM  71 

cause  of  an  insufficient  blood  supply  in  the  brain.  Perhaps 
sleep  has  an  element  of  both  these  types  of  unconsciousness, 
involving  an  altered  brain  circulation  and  the  accumulation 
of  the  poisonous  waste  of  bodily  activity. 

The  unconsciousness  of  sound  sleep  carries  with  it  the  com- 
plete relaxation  of  the  body.  This  is  the  time  when  the  body 
tissues  make  good  their  losses  and  for  these  reasons  no  satis- 
factory substitute  for  sleep  can  be  found.  It  is  probably  this 
complete  relaxation  and  its  accompanying  reduction  of  oxi- 
dation which  makes  a  person  chilly  upon  falling  asleep  in  his 
chair  or  upon  the  couch  in  a  room  which  has  previously 
seemed  warm  enough. 

No  doubt  other  factors  than  nervous  fatigue  are  important 
in  determining  the  amount  of  sleep  required,  since  it  varies 
greatly  in  individuals  and  is  markedly  greater  in  the  young 
than  in  the  old.  Perhaps  the  most  important  factor  here  is 
assimilation.  Heavy  eaters  are  characteristically  heavy 
sleepers,  whereas  "Fletcherites"  testify  that  the  great  reduc- 
tion in  the  amount  of  food  eaten  and  the  completeness  of  its 
mastication  has  reduced  the  amount  of  sleep  which  they  find 
necessary. 

From  seven  to  eight  hours  sleep  is  surely  enough  for  the 
normal  and  healthy  adult  person.  Nor  should  one  conclude 
because  there  is  an  indisposition  to  rise  in  the  morning  that 
he  has  had  too  little  sleep,  it  may  be  laziness  and  not  weari- 
ness. It  has  been  found  by  experiments  that  during  the  first 
two  hours  sleep  is  the  heaviest  and  after  that  the  person  is 
waked  more  easily.  This  does  not  necessarily  mean  that  the 
later  hours  of  sleep  are  not  equally  restful  but  merely  in- 
dicates that  the  nervous  thresliold  has  been  lowered  by  the  rest 
already  secured. 

The  difficulties  in  going  to  sleep  promptly  and  in  sleeping 
soundly  do  not  usually  exist  for  the  normal  individual  if  he 
is  physically  tired.  Wakefulness  often  seems  more  serious 
tluin  it  really  is  because  the  person  may  hear  the  clock  strike 
regularlv  but  vet  obtain  several  hours  of  light  and  dozing 


72  HYGIENE :     DENTAL   AND    GENERAL 

sleep.  Apart  from  physical  exercises  which  induce  bodily 
fatigue  and  secure  a  healthful  sleep  it  is  sometimes  possible 
to  avoid  sleeplessness  by  the  eradication  of  disturbing  factors. 
The  bed  should  be  comfortable,  the  room  dark  and  quiet,  and 
the  ventilation  adequate.  The  person  who  sleeps  where  there 
is  continuous  noise,  may  say  that  he  can  sleep  soundly,  but 
he  is  probably  doing  his  nervous  system  an  injustice  neverthe- 
less because  he  is  partly  wakened  several  times  during  the 
night.  The  banishment  of  exciting  or  worrying  thoughts  and 
the  concentration  of  the  mind  upon  inconsequential  and  hum- 
drum things,  with  the  conscious  attempt  to  relax  the  muscles 
of  the  hands  and  limbs  and  to  adopt  a  slow  rhythm  of  breath- 
ing, may  also  aid  in  promptly  falling  to  sleep. 

Dreams. — The  subject  of  dreams  suggests  itself.  We  must 
leave  their  philosophy  to  the  psychologist,  limiting  ourselves  to 
a  brief  statement  of  their  importance  from  the  hygienic  view- 
point. There  are  two  types  of  dreams,  the  remote  and  the 
recent.  The  remote  type  deals  with  experiences  widely  sep- 
arated from  the  activities  of  the  day,  the  other  type  deals  with 
the  worries  and  problems  of  our  waking  hours.  It  is  the 
latter  and  not  the  former  which  should  be  a  warning  to  us 
that  our  nervous  system  is  not  in  a  rested  and  normal  con- 
dition. 

Chang'e  of  Work. — Another  method  of  resting  the  nervous 
system  is  by  a  change  of  work  which  puts  in  play  a  wholly 
different  set  of  nerve  structures.  The  man  who  has  worked 
over  a  machine  all  day  and  is  thoroughly  tired  m.a.y  rest  his 
nervous  sj'stem  as  well  as  refresh  his  muscular  system  by 
playing  baseball  or  tennis,  but  one  must  be  careful,  in  this 
connection,  not  to  commit  the  fallacy  of  assuming  that  nervous 
excitement,  when  it  involves  the  nervous  structures  already 
tired,  is  rest.  The  man  who  is  tired  from  driving  an  auto- 
mobile may  forget  his  weariness  by  watching  a  moving  picture 
of  hairbreadth  escapes ;  but  he  is  not  rested  thereby  and  it  is 
only  the  strong  stimulation  of  the  overtired  nervous  structures 
which  causes  him  to  forget  his  fatigue  temporarily.     It  is 


HYGIENE   OF    CENTRAL   NERVOUS    SYSTEM  73 

probably  unfortunate  for  the  nervous  system  as  well  as  for 
family  life  that  the  habit  of  quiet  home  reading  has  been 
abandoned  for  a  variety  of  exciting  social  amusements. 

Sunday  Observance. — Sunday  observance  is  a  most  impor- 
tant safeguard  for  the  nervous  system.  In  some  experiments 
carried  out  at  the  Harvard  Medical  School  (reported  by  Mar- 
tin, Withington  and  Putnam,  American  Journal  of  Physiol- 
ogy, 1914,  Vol.  XXXIV)  it  was  shown  that  the  sensory  thres- 
hold, as  measured  by  the  least  electric  shock  which  could  be 
felt  through  two  fingers  of  the  same  hand,  was  lowest  on  Mon- 
day and  highest  on  Saturday.  In  other  words,  the  irritability 
or  sensitiveness  of  the  nervous  system  was  highest  after  the 
day  of  rest  or  change  in  activity  and  was  gradually  reduced 
throughout  the  week.  Apparently  there  is  a  cumulative  fa- 
tigue of  the  nervous  system  by  the  work  of  the  day  which  is 
only  offset  by  Sabbath  rest.  This  may  account  physiologi- 
cally for  the  fact  that  one  day  in  seven  has  been  set  apart  by 
people  of  nearly  all  races  and  religions  as  a  day  of  rest  and 
worship.  It  is  certain  that  the  observance  of  Sunday  as  a  day 
of  quiet  when,  for  a  time  at  least,  the  thoughts  may  be  fixed 
upon  immortal  truths  and  upon  things  entirely  separate  from 
the  struggle  of  the  week  is  much  to  be  desired  in  the  care  of 
the  nervous  system. 

Neurasthenia. — We  have  considered  the  care  of  the  nervous 
system  under  the  normal  conditions  of  life  and  may  now 
turn  our  attention  to  a  discussion  of  the  abnormalities  of  the 
ouerworl-ed  nervous  system.  "We  have  hinted  at  the  cause  of 
this  condition  in  mentioning  cumulative  fatigue  which  in- 
creases during  the  six  working  daj^s  of  the  week.  When  the 
strain  upon  the  nervous  system  becomes  too  great  and  out- 
distances the  ]iormal  rate  of  repair  this  cumulative  fatigue 
results  in  serious  disturbances  ending  in  neurasthenia. 

There  are  a  variet}^  of  causes  for  neurasthenia.  In  a  few 
cases  there  are  hereditary  defects  and  the  individual  is  handi- 
capped from  the  beginning  of  life  with  a  highly  irritable,  hair- 
trigger  nei'vous  mechanism  which  was  his  unfortunate  legacy 


74  HYGIENE :     DENTAL   AND   GENERAL 

from  one  or  both  of  his  parents.  But  in  most  cases  ineffi- 
ciency, discontent  and  lack  of  the  ordinary  degree  of  courage, 
perseverance,  and  kindliness  are  subject  to  hygienic  control 
in  some  degree.  The  causes  which  will  next  receive  consider- 
ation include  overwork,  emotion,  bodily  defects,  eye  strain, 
poor  environment  and  the  like. 

Overwork. — ^By  overworking  the  mind,  w^e  mean  putting 
too  great  a  tax  upon  its  endurance  and  not  a  too  strenuous 
endeavor  to  concentrate  the  mental  facilities.  It  is  a  case  of 
too  long  hours  and  not  too  vigorous  mental  work.  There  is 
a  maxim  for  students  in  regulating  their  hours  of  work  that 
"8  plus  2  equals  10  but  10  plus  2  equals  8"  when  measured 
by  the  effective  work  done.  In  other  words,  there  is  a  time 
limit  in  taxing  the  nervous  system. 

Emotions. — The  discussion  of  emotion  in  previous  chapters 
has  alread}-  suggested  that  not  work  but  worry  is  harmful. 
The  effects  of  the  emotion  upon  the  central  nervous  system 
are  varied  and  important. 

If  we  trace  the  initial  difficulty  of  indigestion  due  to  the 
emotions,  we  find  that  the  food  lies  in  the  stomach  into  which 
no  digestive  juices  have  been  poured  until  abnormal  and  harm- 
ful decomposition  changes  begin  to  take  place.  Then  as  the 
food  is  finally  passed  into  the  intestines  there  is  further  de- 
composition because  the  protein  digestion  has  not  proceeded 
to  a  suitable  degree  in  the  stomach,  and  the  bacteria  in  the  in- 
testines decompose  food  substances  into  soluble  and  harmful 
end  products,  which  are  absorbed  from  the  walls  and  produce 
that  mild  poisoning  known  as  autointoxication.  These  dele- 
terious compounds  have  a  specially  marked  eft'ect  upon  the 
central  nervous  system.  Autointoxication  may  be  produced 
by  continued  unfavorable  emotions  like  worry,  fear,  grief  and 
pity,  and  it  is  increased  by  overeating,  especially  the  over- 
eating of  nitrogenous  foods.  It  is  one  of  the  important 
factors  in  deranging  the  nervous  system. 

The  emotions  have  other  relations  to  the  nervous  system 
than    those    connected    with    digestion.     As    Cannon    clearly 


HYGIENE    OF    CENTRAL    NERVOUS    SYSTEM  75 

showed,  the  emotions  were  designed  as  an  aid  to  activity,  by 
increasing  the  amount  of  sugar  in  the  blood,  producing  a 
marked  secretion  of  adrenalin,  bringing  digestion  to  a  halt 
and  increasing  the  capacity  of  the  skeletal  muscles.  It  is 
normal  and  probably  more  beneficial  to  the  individual  when 
his  strong  emotions  find  an  outlet  in  action  for  then  the  im- 
Ijulses  are  translated  into  muscular  activity.  The  external 
bruises  of  the  school  boy  who  fights  are  perhaps  not  as  serious 
as  the  internal  injury  to  the  nervous  system  if  there  is  no 
outlet  for  his  anger.  Even  when  a  person  has  remained  in- 
active there  is  some  energy  resulting  from  emotion  or  excite- 
ment, for  these  stimuli,  upon  reaching  the  muscles  produce 
balanced  contractions  which  may  be  indicated  by  tenseness 
of  the  muscles  and  features. 

It  would  seem  therefore  that  for  the  normal  and  especially 
for  the  sluggish  individual  a  reasonable  amount  of  emotional 
excitement  may  be  harmless  and  even  desirable.  But  in  so 
far  as  environment  may  be  regulated  to  eliminate  constant 
and  undesirable  emotions  this  should  be  done  and  whenever 
possible  our  emotions  should  be  given  a  physical  outlet,  es- 
pecially those  noble  emotions  which  are  produced  by  beauti- 
ful music  and  other  forms  of  art,  by  the  glories  of  nature,  and 
the  eloquence  of  gifted  speakers.  These  stimuli  should  be 
translated  into  practical  beneficent  action. 

Bodily  Defects. — There  are  many  bodily  defects  which  in- 
jure the  central  nervous-  system  to  a  large  degree.  We  re- 
member that  pain  has  the  same  effect  upon  many  organs  of 
the  body  as  do  rage,  fear  and  anxiety,  and  it  seems  reasonable 
that  many  mild  bodily  ills,  which  are  tolerated  when  they 
should  be  corrected,  will  create  continuous  and  harmful  sen- 
sations in  the  central  nervous  system.  Decayed  teeth, 
troubles  of  tlie  feet,  such  as  fallen  arches,  ill-fitting  shoes,  corns 
and  blisters,  the  wearing  of  orthodontia  appliances  by  children, 
nasal  obstruction  witli  tonsillar  and  adenoid  trouble,  hem- 
orrhoids, and  uterine  displacement  are  examples  of  conditions 
which  should  receive  prompt  attention  not  only  for  their  own 


76  HYGIENE :     DENTAL   AND   GENERAL 

sake  but  for  the  injury  whicli  they  do  the  nervous  system. 

Eye  strain  is  another  important  example.  The  nearsighted 
individual  who  is  trying  in  vain  to  focus  the  eye,  which  is  too 
deep,  in  such  a  way  that  normal  vision  shall  be  effected ;  the 
f  arsighted  individual,  who  must  put  an  extra  strain  upon  the 
eye  to  focus  it  for  near  objects ;  and  the  individual  with  astig- 
matism, who  is  always  straining  the  eyes  in  the  attempt  to 
secure  a  clear  image,  are  all  bound  to  feel  the  effects  upon  the 
nervous  system.  On  the  other  hand  the  correction  of  these 
difficulties  often  makes  a  new  man  or  woman  so  far  as  temper- 
ament and  congeniality  are  concerned.  Perhaps  it  is  the  duty 
of  the  family  to  insist  that  such  conditions  are  corrected  for, 
since  they  have  to  live  with  the  afflicted,  they  may  have  some 
rights  in  the  matter. 

Stiimilants. — Stimulants  also  should  be  considered  in  their 
effect  upon  the  nervous  system.  Physiologists  now  agree  that 
alcohol  is  not  a  stimulant  but  a  narcotic.  The  reason  for  the 
feeling  of  exhiliration  which  follows  a  mild  dose  of  alcohol  is 
due  to  the  paralyzing  of  the  higher  centers  which  have  to  do 
with  inhibition.  When  these  centers  are  shut  out  from  the 
lest  of  the  nervous  system  the  individual  no  longer  feels  the 
restraint  of  dignity  and  propriety.  He  gives  free  rein  to  his 
impulses  and  believes  himself  to  be  the  soul  of  wit  and  the 
prince  of  goodfellows  even  when  his  activities  are  most 
asinine.  As  Professor  Stiles  has  suggested,  alcholic  stimula- 
tion is  like  taking  the  brakes  off  on  a  train  which  is  traveling 
down  hill.  It  is  easy  to  reach  the  lower  level  but  it  is  hard 
to  regain  the  heights. 

In  a  study  of  the  intellectual  capacity  of  a  group  of  stu- 
dents before  and  after  using  alcohol  the  subjects  were  given 
certain  simple  mathematical  problems  which  were  accom- 
plished in  a  given  time  and  the  amount  of  errors  checked. 
Later  in  the  day  after  having  partaken  of  small  quantities  of 
alcohol,  the  students  were  given  similar  problems  to  do  and 
upon  emerging  from  the  room  all  testified  that  they  had  done 
the  work  more  quickly  and  rapidly  than  in  the  first  instance. 


HYGIENE   OF    CENTRAL   NERVOUS   SYSTEM  77 

The  actual  results  were  different  from  their  expectations, 
however.  They  had  taken  longer  to  do  the  work  and  had  been 
less  accurate.  The  temporarj^  banishment  of  care  and  the 
sense  of  obligation  for  the  moment  is  a  pleasure  and  may 
make  the  individual  a  more  gracious  social  being  but  the  re- 
sumption of  responsibilities  after  the  taking  of  alcohol  is  not 
so  easy,  and  good  health  rather  than  this  alternative  should 
be  the  basis  of  our  social  graces. 

Many  of  the  patent  medicines  have  been  shown  to  have  an 
alcoholic  content  greater  than  champagne  as  the  following 
table  shows: 

ALCOHOL  COMPAEISONS 

Beer    41/2% 

Ale    8% 

Champagne    10% 

Swamp  Eoot  9% 

S.  S.  S 15% 

Varuesis 15% 

P'inkham's  Vegetable  Compound   15% 

Warner's  Safe  Eemedy 15%% 

Tanlac    16% 

Pepto-Mangan    16% 

Hood 's  Saisaparilla 16%% 

Vinol 18% 

Manola 18% 

Wincarnis    19% 

Paine 's  Celery  Compound 19^4o% 

Peruna    '. 20% 

Wine  of  Cardui    20% 

Plant  Juice   20% 

Hostcttcr 's   Bitters    25% 

It  may  not  be  inappropriate  therefore  to  classify  such  sub- 
stance as  stimulants  especially  since  in  many  cases  their  real 
medicinal  value  is  seriously  in  question.  The  man  who  is 
foolish  enough  to  prescribe  such  a  remedy  for  himself  instead 
of  seeking  the  advise  of  a  good  physician  for  his  ills,  ought 
to  know  what  it  really  is  which  makes  him  ' '  feel  better ' '  when 
he  drugs  the  system  with  a  patent  medicine  cocktail. 

Tea,  coffee,  and  cocoa  are  not  narcotic  but  arc  true  stimu- 


78  HYGIENE:     DENTAL    AND    GENERAL 

lants  and  their  effect  on  the  body  is  to  increase  activity.  For 
most  people  their  use  in  reasonable  quantities  is  not  harmful. 
']''here  are  people,  however,  who  find  that  one  or  the  other  of 
these  drinks  is  a  definite  injury.  To  be  of  greatest  value 
they  should  not  be  used  regularly  but  only  when  some  un- 
usual demand  is  to  be  placed  upon  the  nervous  system. 

The  Neurasthenic. — We  should  consider  Avhat  is  meant 
by  the  functional  disorder  neurasthenia  or  as  it  is  called  in 
some  of  its  milder  stages,  nervous  fatigue  or  nervous  prostra- 
tion. This  is  a  type  of  disease  which  shows  no  lesions  upon 
postmortem  examination.  It  is  functional  rather  than  struc- 
tural. As  the  state  of  nervous  impairment  progresses  the  in- 
dividual indicates  his  condition  by  his  demonstrativeness.  He 
appears  to  be  m  a  mild  state  of  intoxication  and  indeed  the 
accumulation  of  fatigue  products  in  the  brain  may  act  in 
somewhat  the  same  fashion  as  an  alcoholic  stimulant  and  may 
manifest  itself  in  bodily  movements  and  muscular  contrac- 
tions. 

The  neurasthenic  is  dissatisfied  with  everything  around  him 
because  he  is  in  an  extremely  sensitive  condition.  The  room 
is  too  hot  or  too  cold,  there  is  too  much  light  or  too  much 
noise.  Impulses  are  sent  to  all  parts  of  the  body  upon  the 
slightest  provocation.  The  skin  is  readily  flushed  or  takes 
on  the  goose-flesh  appearance,  the  heart  is  irregular,  the  di- 
gestion f aultj ,  and  the  urine  widely  variable  in  composition. 
And  perhaps  worse  than  all  is  the  subjective  state,  which  is 
one  of  self-pity  and  disregard  for  the  feelings  of  others,  a 
condition  separated  from  insanity  only  by  the  fact  that  all 
the  worries  have  some  foundation — though  often  slight — in 
fact,  and  are  not  wholly  imaginary.  The  neurasthenic  is 
often  not  responsible  for  his  condition.  It  may  have  been 
brought  on  by  circumstances  over  which  he  had  no  control. 
Nevertheless,  it  is  extremely  difficult  to  treat  him  with  un- 
mitigated kindness.  It  must  be  remembered  that  the  troubles 
of  which  the  neurasthenic  complains  are  real  to  him  and  he 


HYGIENE    OP    CENTRAI.    NERVOUS    SYSTEM  79 

must  be  treated  with  the  consideration,  tolerance  and  tem- 
perance Avhich  this  broad  perspective  would  suggest. 

Treatment. — In  describing  the  cause  of  neurasthenia  as 
nervous  fatigue  the  remedy  has  naturally  suggested  itself  as 
suitable  rest  for  the  nervous  system.  Bodily  defects  must  be 
first  corrected  and  then  physical  exercise,  which  will  concen- 
trate the  mind  upon  other  things  than  the  worries  of  the  in- 
valid, and  sufficient  sleep  are  important  factors.  Nervous 
fatigue  yields  more  readily  to  these  corrective  measures  in  its 
incipient  than  in  its  latter  stages. 

The  dentist  may  frequently  be  of  aid  to  the  neurasthenic 
by  encouraging  him  in  a  program  of  physical  upbuilding  and 
by  assuring  him  that  better  teeth  and  the  correction  of  other 
bodily  defects  will  improve  his  health  and  relieve  his  nervous- 
ness. Such  a  patient  in  the  dentist's  chair  should  be  treated 
with  kindness,  sympathy,  and  encouragement  but  with  some 
degree  of  firmness. 


CHAPTER  V 

THE  HYGIENE  OF  REPRODUCTION 

The  Problem  Defined. — The  problem  of  reproduction  in 
its  broadest  sense  involves  the  rej)laeing  of  one  generation  by 
another  in  the  best  possible  manner.  This  includes  compli- 
ance with  the  laws  of  heredity,  a  knowledge  of  the  effects 
which  the  conduct  of  life  may  have  upon  the  offspring,  the 
best  possible  supervision  over  the  hygiene  of  pregnancy  and 
the  early  days  of  infant  life,  and  the  proper  regulation  of 
the  sex  life. 

HEREDITY 

Our  knowledge  of  heredity  has  expanded  rapidly  during 
the  past  few  years.  We  have  here,  however,  only  sufficient 
space  to  mention  some  of  those  facts  which  are  important  in 
guarding  against  the  perpetuation  of  undesirable  traits  and 
physical  conditions  in  offspring.  The  development  of  the 
subject  has  come  from  two  lines  of  study,  researches  upon 
human  heredity  (eugenics)  begun  by  Galton  and  researches 
in  plant  and  animal  breeding  (genetics)  begun  by  Mendel. 

Mendelian  Inheritance. — Mendel's  law  enunciates  the 
principle  that  opposing  characteristics  in  the  male  and  female 
parents  do  not  blend  in  the  offspring  but  the  heredity  units 
or  genes  remain  distinct  in  the  germ  cells  of  the  offspring 
recombining  in  future  generations  according  to  the  law  of 
probability  and  chance. 

To  illustrate  by  an  example  from  Mendel's  work:  when  a 
pea  plant  which  produces  peas  having  a  green  color  is  crossed 
with  one  producing  peas  of  yellow  color  all  the  peas  produced 
in  the  first  generation  are  of  a  yellow  color  but  if  plants  of  this 
first  hybrid  generation  are  crossed  among  themselves  the  peas 
produced  in  the  second  generation  are  in  a  definite  ratio  of 
three  yellows  to  one  green. 

80 


HYGIENE   OF    REPRODUCTION  81 

This  law  may  be  illustrated  also  from  animal  heredity. 
Among  guinea  pigs  the  crossing  of  a  black  strain  with  a  white 
strain  produces  in  the  first  generation  only  black  offspring 
but  if  these  pigs  are  bred  among  themselves  the  resulting  off- 
spring are  in  the  ratio  of  three  black  pigs  to  one  white  one. 

These  results  are  most  clearly  understood  in  terms  of  the 
presence  and  absence  theory  which  assumes  that  the  yellow 
pea  and  the  black  guinea  pig  possess  factors  in  the  germ  cell 
for  yellow  and  black  color,  respectively,  and  that  these  color 


Fig.    13. — Inheritance   in   guinea   pigs   showing   where    the   color    (black)    dominates 
over  another  color  (white).     (Kelicott.) 

factors  are  lacking  in  the  green  pea  and  the  white  pig.  Such 
a  characteristic  appears  whenever  it  is  present  in  one  or  both 
of  the  germ  cells  united  to  create  the  new  individual.  We 
have  here  an  explanation  of  the  fact  that  offspring  of  the 
first  generation  all  show  a  particular  characteristic  which  has 
been  inherited  from  one  of  the  parents.  "We  call  such  a  char- 
acteristic as  blackness  in  the  guinea  pig  a  dominant  character- 
istic and  the  white  color  a  recessive  characteristic.  The  fol- 
lowing diagram  illustrating  the  inheritance  in  guinea  pigs 
shows  why  the  first  generation  is  completely  black.  All  of 
the  ova  produced  by  the  female  guinea  pig  contain  the  char- 
acteristic for  blackness  and  although  they  are  united  with 
sperms  which  lack  this  characteristic  for  blackness  they  still 


82  HYGIENE:     DENTAL    AND    GENERAL 

cany  the  characteristic  to  the  fertilized  egg  which  is  the  be- 
ginning of  the  existence  for  the  new  individual. 

It  may  help  us  to  understand  the  law  better  if  we  consider 
the  explanation  afforded  by  the  general  belief  that  the  chromo- 
somes are  bearers  of  the  hereditary  characteristics.  The 
reader  will  recall  from  elementary  studies  of  biology  that  the 
chromatin  or  deeply  staining  substance  of  the  cell  nucleus 
arranges  itself  into  short  threads  called  chromosomes  when- 
ever there  is  a  cell  division.  The  number  of  these  chromo- 
somes is  constant  for  any  species  of  animal.  The  number  in 
all  of  the  hody  cells  is  twice  that  in  the  mature  sex  cell.  In 
other  words,  the  final  maturation  processes  of  sex-cell  develop- 
ment allow  a  separation  of  the  chromosomes  into  two  sets  or 
groups  so  that  there  may  he  two  kinds  of  sperms  and  two 
kinds  of  ova  so  far  as  the  inheritance  or  non-inheritance  of 
any  characteristic  is  concerned. 

Eeturning  to  our  example  of  the  inheritance  of  color  in 
guinea  pigs  we  assume  that  the  black  color  is  produced  by  a 
special  factor  for  pigmentation  which  is  present  in  the  sex 
cells  of  the  black  pig  and  absent  in  those  of  the  white  pig. 
It  would  appear  that  this  factor  is  present  in  a  chromosome 
inlierited  from  the  female  parent  but  absent  in  the  corres- 
ponding chromosome  inherited  from  the  male  parent.  It 
would  therefore  be  present  in  all  of  the  body  cells  of  the  hy- 
brid but  when  this  pair  of  chromosomes  again  become  sep- 
arated in  the  production  of  sex  cells  they  would  produce 
cells  of  different  types.  Therefore,  we  may  have  from  this 
generation  of  hybrids,  ova  containing  a  factor  for  pigmen- 
tation and  ova  lacking  the  factor  for  pigmentation.  Like- 
wise, we  may  have  spermatozoa  with  this  factor  and  others 
without  it.  so  that  there  are  four  possibilities  in  the  mating 
of  cells  within  the  uterus  which  must  be  in  reality  a  matter 
of  chance.  The  female  cell  with  the  character  for  blackness 
may  unite  with  the  male  cell  also  having  that  characteristic 
and  in  that  case  the  offspring  produced  receives  the  same  in- 
heritance from  both   parents  so  far  as  this  characteristic  is 


HYGIENE    OF    KEI'KODrt'TiON 


83 


concerned,  and  therefore  it  is  a  "pure  black''  which  will 
always  produce  black  offspring.  There  is  an  exactly  opposite 
possibility,  namely,  a  union  of  two  cells  neither  of  which  has 


Fig.  16. — Diagram  illustrating  the  mechanism  by  which  tl^e  unit  factor,  cohjr, 
is  inherited  in  guinea  pigs.  Animal  A  is  a  black  female  of  pure  stock.  Such  an 
animal  is  called  homozygous  and  all  of  its  sex  cells  are  alike  in  carrying  the 
unit  character  in  question.  Anima!  B  is  a  homozygous  white  male;  none  of  the  se.x 
cells  have  the  characteristic  for  blackness.  Animals  C  (female^  and  D  (male) 
are  hybrids.  In  each  case  half  of  the  sex  cells  carry  the  characteristic  for 
blackness  and  half  of  them  lack  this  characteristic.  W'hen  C  and  'D  are  crossed 
the  offsi)ring  of  the  second  generation  are  in  the  ratio  to  three  black  to  one 
white.  The  diagram  illustrates  each  i)ossible  chance-combination  of  s])erm  and 
egg  and  it  will  be  seen  that,  of  the  second  generation  animals,  E  is  homozygous, 
1'"   and   C,   are    heterozygous   like    C   and   D,   and    1 1    is   a   homozygous   white. 


the  characteristic  for  blackness.     Such  a  union  results  in  a 
white  pio-  of  pure  stock  so  far  as  color  is  concerned. 

Two  other  possibilities  involve  the  mating'  of  a  foualc  cell 
couiahi'nui  the  cliarncteristic  witli  a  maJe  cell  Idrklnf/  the  cliar- 


84 


HYGIENE :     DENTAL   AND    GENERAL 


acteristic  or  the  exactly  opposite  condition.  In  either  case 
we  have  a  hybrid  individual  like  the  parents,  that  is,  one  and 
only  one  of  the  pair  of  chromosomes  with  which  the  color 


Fig.  17.— Eminent  Twins.  Edwin  P.  Grosvenor  (left),  prominent  New  York 
lawyer,  and  his  twin  brother  Gilbert  Grosvenor  (right),  President  of  the  National 
Geographic    Society.      (Photograph   from   Gilbert   Grosvenor.) 

factor  is  connected  contains  the  characteristic.  Such  animals 
are  black  in  color  because  a  pigment  factor  is  present,  al- 
though only  in  half  quantity,  and  if  again  bred  among  them- 


HYGIENE   OF    REPRODUCTION  85 

selves  we  once  more  have  a  3-1  ratio,  that  is,  three  black  off- 
spring to  one  white.  Naturally  since  this  ratio  depends  upon 
probability  or  chance  it  is  not  exact.  However,  the  greater 
the  number  of  offspring  the  more  exact  is  the  ratio.  This 
three  to  one  ratio  is  in  reality  a  ratio  of  one  pure  black:  2 
hybrid  blacks :  1  pure  white.  Such  an  hereditary  trait  as  the 
one  just  described  is  called  a  unit  character. 

The  study  of  genetics  has  taught  us  that  many  character- 
istics are  inherited  like  the  unit  factors  mentioned  above. 
That  being  the  case,  it  is  obvious  that  these  characteristics 
can  be  mingled  by  crossing  different  types  and  can  be  recom- 
bined  in  new  combinations.  For  example,  it  might  be  pos- 
sible to  cross  a  round  red  tomato  with  a  yellow  pear-shaped 
tomato  and  by  continued  breeding  and  careful  selection  secure 
a  pure  strain  of  red  pear-shaped  tomatoes.  This  indeed  is  the 
principle  and  the  explanation  of  the  wonderful  work  accom- 
plished by  Luther  Burbank  in  plant  breeding. 

We  can  but  marvel  at  the  miracle  of  nature  displayed  in 
beredity.  From  each  mating  of  sex  cells,  all  of  which  look 
exactly  alike  when  viewed  with  the  highest  power  of  the  micro- 
scope, nature  produces  an  individual  different  in  character- 
istics from  any  other  of  the  millions  of  people  who  inhabit  the 
globe.  It  is  difficult  to  explain  how  so  many  characteristics 
can  be  arranged  spacially  in  the  tiny  germ  cell  unless  we  can 
conceive  tliat  these  characteristics  are  caused  by  the  infinite 
varieties  in  molecular  pattern  which  are  possible  in  the  highly 
complex  chromatin  substances.* 

The  mechanism  of  inheritance  is  in  no  way  better  illustrated 
than  in  the  complete  similarity  of  identical  twins  which  re- 
sult from  the  separation  of  the  embryo  in  its  two-celled  stage. 
Such  twins  must  therefore  receive  identical  hereditary  fac- 
tors. Compare  the  records  of  the  Grosvenor  twins.  As  stu- 
dents at  Amherst  College  they  divided  highest  honors  in 

*Miescher  has  shown  that  a  molecule  of  albumen  with  forty  carbon  atoms  may 
have  as  many  as  one  billion  stereoisomers,  in  protoplasm  there  are  many  kinds  of 
albumen  and  other  proteins,  some  with  probably  more  than  700  carbon  atoms. — 
Conklin. 


86  HYGIENE  :     DENTAL   AND    GENERAL 

the  classroom  and  on  the  tennis  field.  Both  have  since 
achieved  distinction,  one  as  builder  and  director  of  the  Na- 
tional GeograjDhic  Society,  and  the  other  as  Assistant  Attor- 
ney-General and  partner  in  one  of  the  most  important  law 
firms  in  America.  They  have  never  varied  more  than  a  pound 
in  weight.  In  college  their  grades  never  varied  more  than  one- 
tenth  of  one  per  cent.  Although  absolutely  dependent  upon 
glasses,  each  can  wear  the  other's.  Most  of  their  tastes  are 
similar. 

How  Sex  in  the  Offspring  Is  Determined. — There  has  al- 
ways been  considerable  speculation  as  to  how  sex  in  offspring 
is  determined,  because  the  question  is  of  vital  interest  to  par- 
ents who  have  a  preference  for  either  a  son  or  a  daughter; 
and  it  is  interesting  to  find  that  the  explanation  offered  by 
Mendelian  studies  in  heredity  and  the  microscopic  studies  of 
cell  structure,  which  have  for  the  most  part  been  developed 
by  Morgan,  Wilson,  and  other  American  investigators,  indi- 
cate that  sex  in  the  offspring  cannot  be  controlled.  We  said 
previously  that  the  body  cells  of  animals  contain  twice  as 
many  chromosomes  as  do  the  sex  cells.  We  must  modify  this 
general  statement  by  saying  that  in  the  male  of  certain  spe- 
cies this  is  not  true.  In  such  animals,  of  which  it  seems  that 
man  is  an  example,  there  is  a  chromosome  which  students  of 
heredity  speak  of  as  the  sex  chromosome. 

Investigators  believe  that  among  humans  all  body  cells  in 
the  female  contain  48  chromosomes.  This  is  true  of  the  sex 
cells  up  to  the  time  of  the  maturation  process  when  the  reduc- 
tion takes  place  and  the  ripe  ova  are  found  to  have  2-1:  chromo- 
somes. Among  males  the  body  cells  appear  to  contain  47 
chromosomes  and  when  the  maturation  process  takes  place 
the  odd  chromosome  or  sex  chromosome  as  it  is  called  goes  to 
but  half  of  the  cells  resulting  from  the  last  division.  We 
therefore  have  two  kinds  of  spermatozoa  in  man,  one  having 
23  chromosomes,  the  other  having  23  chromosomes  plus  the 
sex  chromosome  or  24.  When  the  23  chromosome  sperm 
unites  with  the  egg  we  have  the  beginning  of  a  new  individual 
of   47   cliromosomes   or   a    male.     When   tlie   24   chromosome 


HYGIENE    OF    REPRODUCTIOX 


87 


sperm  unites  with  the  egg  we  have  a  new  iudividual  of  48 
chromosomes  or  a  female.  Femaleness,  then,  is  produced  by 
the  presence  of  two  sex  determiners,  that  is,  it  is  an  added 
characteristic  superimposed  upon  maleness.  *  The  determina- 
tion of  sex  is  therefore  a  matter  of  chance. 

Sex-Linked  Characters. — Apparently  the  causative  fac- 
tors of  certain  other  characteristics  are  located  in  the  cliromo- 
some  which  determines  sex  and  such  unit  characters  are  called 
sex-linked.     Remembering  the  nature  of  the  sperm  cells  de- 


APPLICATIOM  or  nE/IItUAn  TKiXlPLLo    TO   HurXM    hUtRllAICL 

TRAfisrnssion   or  Color  rsjntiiv^>& 


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ncmex.  GouK  fium 


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^^  =  CiE.rE.cnvii  LYt 
T     =rEA4LE. 


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GRAnifiilLDRm. 

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Tflf.  HALE  MAS  cnt  Of"  TO5X  3LX 

oiajnoacs.  the,  nrvux  1-1.'^  tvvq 


Fig.    IS. — Transmission    of   color    lilindness. 

scribed  above,  we  see  that  a  sex-linlved  character  in  a  man 
might  be  transmitted  to  lus  daugliter  but  not  to  his  son,  if  it 
were  a  dominant  character.  If  it  were  a  recessive  character 
it  could  not  be  transmitted  to  any  of  the  children  from  the 
father  provided  the  mother  were  normal  in  this  respect. 
Recessive  sex-linked  characteristics  when  transmitted  by  the 
mother  would  be  apparent  only  in  tbe  sons. 

Color-blindness  gives  an  examph:'  of  this  kind  of  inliei-ilance 


88  HYGIENE:     DENTAL   AND    GENERAL 

and  since  it  is  a  recessive  characteristic  a  color  blind  man 
need  have  no  fear  of  transmitting  the  defect  to  his  children 
if  he  marries  a  woman  with  no  taint  of  this  defect.  This 
defect,  however,  may  be  passed  on  through  his  daughters  to 
his  grandsons  but  not  to  his  granddaughters.  The  color  blind 
woman  on  the  other  hand  if  married  to  a  normal  man  even 
though  she  inherited  color-blindness  from  both  her  parents 
would  not  transmit  the  defect  to  her  daughters.  Her  sons, 
however,  would  all  be  color  blind.  The  fact  that  this  charac- 
teristic is  located  in  the  sex  chromosome  explains  why  color- 
blindness is  more  common  in  men  than  in  women.  Being  re- 
cessive it  is  not  apparent  in  the  female  unless  it  is  inherited 
from  both  parents,  while  in  the  male  it  is  directly  received 
from  the  mother  since  it  is  not  counter-balanced  by  a  normal 
inheritance  from  the  father. 

Inherited  Diseases  and  Abnormalities. — There  are  several 
unit  characters  which  have  already  been  discovered  in  human 
heredity.  Some  of  these  are  diseases  but  fortunately  for  the 
race  these  diseases  are  usually  recessive  and  their  evil  effects 
may  be  counteracted  by  intermarriage  with  a  normal  stock. 
It  must  be  remembered  in  this  connection  that  pure  strains 
for  many  characteristics  are  almost  never  to  be  found  where 
inter-racial  marriages  have  taken  place  for  several  genera- 
tions. '. 

The  following  table  shows  some  of  the  conditions  in  man 
which  are  inherited  according  to  Mendelian  principle : 

MENDELIAN   INHEEITANCE   IN  MAN 
(Teratological  and  Pathological  Clvaraeters) 
Dominant  Recessive 

GENEEAL  SIZE: 

Achondroplasy    (Dwarfs  -with  short  stout       Normal 
limbs  but  with  bodies  and  heads  of 
normal  size) 
Normal  Size  True    dwarfs    (With    all 

parts   of  the  body  re- 
duced in  proportion.) 


HYGIENE   OF   REPRODUCTION 


89 


HANDS  AND  FEET: 

Brachydactyly  (short  fingers  aud  toes) 
Syndactyly  (Webbed  fingers  and  toes) 
Polydactyly    (Supernumerary  digits) 

SKIN: 

Keratosis   (Thickening  of  Epidermis) 
Epidermolysis     (Excessive    formation     of 

blisters) 
Hypotrichosis      (Hairlessness      associated 
with  lack  of  teeth) 

KIDNEYS: 

Diabetes   insipidus 
Diabetes  mellitus 
Normal 

NEEVOUS  SYSTEM: 
Normal 


Normal 


Normal 


Normal 
Normal 

Huntington 's   Chorea 
Muscular  Atrophy 
EYES: 

Pigmentary  Degeneration  of  Ketiua 
Glaucoma  (Internal  pressure  and  swelling 

of  eyeball) 
Coloboma  (Open  suture  in  iris) 
Displaced  lens 

EAES: 
Normal 
Normal 


Normal 
Normal 
Normal 

Normal 
Normal 
Normal 

Normal 
Normal 

Alkaptonuria  (Urine  dark 
after  oxidation) 

Multiple  Sclerosis  (Dif- 
fuse degeneration  of 
nerve  tissue) 

Friedrich's  Disease  (De- 
generation of  upper 
part  of  spinal  cord) 

Meniere 's  Disease  (Dizzi- 
ness and  roaring  in 
ears) 

Chorea  (St.  Vitus  Dance) 

Thomsen's  Disease  (Lack 
of  Muscular  tone) 

Normal 

Normal 

Normal 

Normal 
Normal 

Normal 


Deaf -mutism 

Otosclerosis  (Thickened 
tympanus  with  hard- 
ness of  hearing) 


90  HYGIENE :     DENTAL   AND    GENERAL 

{Sex-Liiiked  Characters) 

Recessive  characters,  appearing  in  male  when  simplex,  in  female 
only  wlien  duplex. 

Normal  Gower's    Muscular    Atro- 

phy 
Normal  Haemoijliilia    (Slow   clot- 

ting  of   blood) 
Normal  Color  Blindness   ( Dalton- 

ism j    inability    to    dis- 
'  tinguish       red       from 

green) 
Normal  Night  Blindness   (Inabil- 

ity   to     see    by    faint 
light) 
Normal  Neuritis  Optica  (Progres- 

sive   atrophy    of    optic 
»  nerve) 

It  is  believed  by  some  investigators  tbat  many  other  char- 
acteristics relating  to  normal  variations  of  the  hair,  eye, 
skin,  countenance,  temperament,  intellect  and  nervous  system 
are  inherited  in  Mendelian  fashion.  It  is  difficult  to  secure 
evidence  in  human  heredity  and  the  way  in  which  many  of 
these  characteristics  are  inherited  is  still  in  doubt. 

Mentality  and  Heredity. — The  importance  of  good  he- 
redity has  long  been  realized  in  characteristics  or  combina- 
tions of  characteristics  where  the  Mendelian  principle  is  not 
present  or  where  it  has  been  impossible  to  demonstrate  it.  A 
case  in  point  is  the  inheritance  of  mental  equipment.  Mental 
ability  is  without  doubt  inherited  as  there  is  a  high  correlation 
between  the  mentality  of  fathers  and  sons,  and  between  the 
mentality  of  brothers.  There  is  also  a  high  correlation  be- 
tween the  mental  abilities  of  husbands  and  wives  since  there 
is  usually  selective  mating  through  which  men  choose  wives 
like  themselves  in  mentality.  (In  contradiction  to  a  popular 
belief  most  people  marry  ''likes"  not  opposites.)  This  helps 
to  raise  the  father  and  son  correlation. 

The  inheritance  of  mentality  is  not  like  the  inheritance  of 
a  dominant  or  recessive  unit  character.     In  mentality,  phys- 


HYGIENE    OF    REPRODUCTION  91 

ical  stature,  size  and  some  other  characteristics  the  offspring 
of  widely  different  parents  seems  to  be  intermediate  between 
the  two.  It  would  seem  that  there  is  either  a  blending  of 
characteristics  or  else  the  quality  in  question  is  produced  by 
many  or  "multiple"  unit  factors.  In  the  latter  case  if  the 
father  possessed  twenty  factors  for  mental  ability  and  the 
mother  ten  the  offspring  would  receive  about  fifteen  and 
would  therefore  be  intermediate  in  condition  thus  giving  the 
appearance  of  "blending  inheritance." 

Of  course  the  question  of  environment  enters  here  since 
children  of  most  brilliant  parents  would  have  the  best  sur- 
roundings. It  is  not  possible  to  give  a  general  answer  to  the 
question  as  to  which  is  the  more  important,  heredity  or  en- 
vironment. Color  blindness  is  due  to  heredity ;  voice,  speech, 
manners  and  indeed  business  success  may  be  due  to  environ- 
ment. Thc-re  is  good  evidence  of  the  importance  of  heredity, 
however,  in  the  production  of  essential  mental  and  physical 
traits  like  long  life  and  good  constitution.  For  example.  Dr. 
F.  A.  Woods  has  shown  that  the  correlation  between  father 
and  son  in  attaining  distinction  is  as  high  in  America  as  in 
the  old  countries  of  Europe.  Now  if  success  were  entirely  a 
matter  of  environment  or  "equal  chance"  there  would  be  a 
lower  correlation  in  America  where,  as  in  a  young  country, 
the  opportunities  are  much  more  nearly  equal  than  in  the  old 
countries  with  established  castes.  The  "little  red  school 
house"  caniiof  "give  every  boy  an  equal  chance  to  be  presi- 
dent." All  men  may  be  "created  free"  but  they  are  not  all 
"created  equal." 

Dr.  Woods  has  shown  that  if  the  people  in  the  Hall  of  Fame 
on  the  Hudson  were  stood  in  line  with  the  first  beneath  the 
center  of  tlie  dome  in  the  capitol  at  Washington  the  line  made 
by  the  thirty  would  not  reach  outside  the  room.  If  the  people 
of  distinction  as  recorded  in  standard  biographical  diction- 
aries were  stood  behind  them  the  line  would-  reach  outside  the 
capitol  and  be  continued  for  a  mile  or  so  down  Pennsylvania 
Ave.    If  tlicir  (•()iit(Miii)ovaries  (the  i-emaiiidor  of  the  American 


92  HYGIENE:     DENTAL   AND   GENERAL 

people)  were  stood  in  line  behind  them  the  line  would  stretch 
to  Chicago,  on  to  San  Francisco  and  up  to  Alaska.  Of  the  last 
group  one  in  500  would  be  closely  related  to  a  man  of  distinc- 
tion, of  the  middle  group  one  in  four  would  have  a  near  rel- 
ative of  distinction  and  of  the  first  group  the  people  would 
average  one  such  near  relative  apiece.  Apparently  there  are 
'■'good  strains"  of  human  stock.  (For  further  evidence  the 
reader  is  referred  to  the  recent  and  delightful  book  on  Applied 
Eugenics,  by  Poponoe  and  Johnson.) 

We  have  the  story  of  the  family  of  the  illustrious  Jonathan 
Edwards  which  shows  innumerable  examples  of  the  highest 
intellectual  and  moral  worth  among  its  descendants.  On  the 
other  hand  we  have  the  story  of  the  Jukes  family  investigated 
by  Dugdale  and  concerning  which  we  find  the  following  sta- 
tistics. In  five  generations  of  the  descendants  of  a  worthless 
fisherman  there  were  1200  persons,  including  200  who  married 
into  the  family ;  the  history  of  1040  of  these  people  is  partly 
known  or  well  known.  About  300  died  in  infancy,  of  those 
remaining  7  were  murderers,  60  were  habitual  thieves,  130 
were  convicted  criminals,  140  were  physically  wrecked  by 
their  own  diseases  and  wickedness,  more  than  half  of  the 
women  were  prostitutes,  and  310  were  professional  paupers 
living  in  almshouses  a  total  of  2300  years,  not  one  of  these 
people  had  a  common  school  education  and  only  20  learned 
a  trade,  10  of  whom  learned  it  in  a  state  prison.  Here  of 
course  it  is  not  easy  to  separate  heredity  and  environment. 

Perhaps  a  somewhat  more  striking  example  of  the  import- 
ance of  heredity  is  to  be  found  in  the  story  of  the  ' '  Kallikak ' ' 
family  which  has  been  cited  by  Dr.  Henry  Goddard  (The  Kal- 
likak Family,  a  Study  in  Heredity  and  F eehle-mindedness) . 
Here  is  the  story  of  a  revolutionary  soldier  who  took  advan- 
tage of  a  feeble-minded  girl.  From  this  indulgence  a  feeble- 
minded son  was  born,  from  him  there  descended  a  long  line 
of  degenerates,  similar  to  those  we  have  just  described  among 
the  Jukes  family.  After  the  war,  Kallikak,  who  was  of  good 
English   descent,   married  a   Quaker   girl  of   good   ancestry 


HYGIENE   OF    REPRODUCTION  93 

and  from  this  legitimate  union  a  long  line  of  descendants  has 
been  traced,  all  of  whom  held  position  in  the  upper  walks  of 
life  and  none  of  whom  were  criminals  or  ne'er-do-wells. 

Feeble-mindedness. — The  normal  individual  must  accept 
his  responsibility  for  race  betterment  in  deciding  the  question 
of  marriage,  but  the  problem  involved  in  preventing  the  prop- 
agation of  the  mentally  deficient  is  one  which  society  must 
handle.  These  feeble-minded  people  are  divided  into  three 
groups  according  to  mentality.  The  idiot  has  a  mental  age  no 
greater  than  that  of  a  normal  child  of  two  years,  among  im- 
'beciles  the  mental  age  remains  at  about  that  of  the  four  year 
period,  while  the  moron  has  a  mental  age  not  greater  than  that 
of  a  twelve  year  old  child. 

None  of  the  four  measures,  which  have  been  proposed  for 
controlling  the  propagation  of  defectives  is  fully  satisfactory. 
These  measures  are  (1)  education,  (2)  legislation,  (3)  segre- 
gation, and  (4)  surgery.  Education  of  the  general  public 
may  make  society  more  alert  to  this  problem  for  it  is  certainly 
startling  when  we  realize  that  America  has  about  half  a  mil- 
lion insane,  feeble-minded,  epileptic,  blind  and  deaf;  80,000 
prisoners,  and  100,000  paupers,  who  are  supported  at  a  cost 
well  over  a  hundred  million  dollars  a  year.  Laws  limiting  the 
marriage  of  feeble-minded  people  have  been  enacted  in  many 
states.  Segregation  is  an  ideal  procedure  where  it  can  be 
applied  but  it  is  hopeless  to  attempt  to  secure  all  the  afflicted 
and  to  place  them  in  segregation  hospitals.  Resorting  to 
surgery,  the  simple  operation  of  severing  the  vas  deferens 
or  the  slightly  more  complicated  operation  of  severing  the 
Fallopian  tube,  has  been  practiced  but  there  is  a  serious 
danger  from  the  misuse  of  this  surgical  measure  and  a  prac- 
tical difficulty  in  determining  where  it  shall  be  applied. 

Heredity  and  Conduct. — A  somewhat  different  phase  of  the 
Hygiene  of  Reproduction  concerns  a  question  which  is  natu- 
rally and  often  asked,  namely,  what  effect  will  one's  habits, 
virtues,  and  vices  have  upon  the  offspring.  The  present 
theor3^  regarding  the  inheritance  of  acquired  characteristics 


94  HYGIENE  :     DENTAL    AND    GENERAL 

is  indicated  in  the  surgical  experiment  of  Dr.  W.  E.  Castle 
in  which  the  ovaries  from  a  small  black  guinea  pig  M^ere  trans- 
planted into  an  albino  (pure  white)  guinea  pig,  which  was 
later  mated  with  another  albino.  The  offspring  produced 
were  black.  This  experiment  shows  that  the  hereditary  qual- 
ities lay  in  the  germ  cells  and  not  the  body  as  a  whole. 

"We  know  also  that  embryologically  the  sex  cells  are  early 
separated  from  the  rest  of  the  body  and  that  the  ova  them- 
selves are  already  formed  in  full  number  at  the  time  of  birth. 
Mutilation  experiments,  like  cutting  off  the  tails  of  mice  for 
several  generations,  have  failed  to  show  any  shortening  effect 
in  inherited  character. 

One  may  say  that,  from  the  standpoint  of  the  race,  the  germ 
cell  is  of  greater  importance  than  the  individual.  This  in 
general  is  true,  for  a  person  is  like  the  father  merely  because 
he  is  decended  from  the  same  line  of  similar  germ  cells.  The 
children  of  soldiers  mutilated  in  war  will  be  normal  in  every 
respect  so  far  as  the  influence  of  these  mutilations  is  con- 
cerned. An  injury  to  the  germ  cells  is  much  more  serious  than 
an  injury  to  the  body  tissues  of  the  individual. 

The  number  of  cells  of  the  body  which,  through  one's  de- 
scendants, may  outlive  the  span  of  his  own  life  is  determined 
by  the  number  of  his  children.  We  cannot  change  the 
hereditary  characteristics  which  are  embodied  in  these  cells, 
but  we  should  remember  that  these  cells  are  a  living  part  of 
the  body  and  that  they  are  subject  to  some  of  the  same  in- 
fluences which  injure  other  tissues.  We  would  expect  to  find 
the  greatest  vitality  in  those  cells  which  are  in  a  normal  and 
healthy  body. 

Certain  poisons,  which  are  distributed  through  the  circula- 
tion, can  reach  these  cells  and  a  poison  which  is  capable  of 
serious  injury  to  the  growing  or  adult  organism  may  thus  be 
expected  to  reach  in  its  baleful  influences  to  the  unfertilized 
sex  cell.  Lead  is  such  a  poison.  When  it  gradually  accumu- 
lates in  tlie  system  it  not  only  injures  the  l)ody  of  the  parent 


HYGIENE    OF    REl'RODl   ( "I'lOX  95 

but  it  injures  the  germ  cells  as  well.  When  there  is  serious 
lead  poisoning  in  either  the  father  or  the  mother  the  number 
of  still-born  children  is  greatly  increased  and  those  who  do 
live  are  often  of  inferior  vitality. 

The  poison  from  syphilis  is  a  substance  which  has  most 
harmful  effects  especially  upon  the  nervous  system  of  children. 
This  disease,  moreover,  as  we  shall  see  later,  may  be  inherited 
in  the  active  and  contagious  form.  Gonorrhea  is  not  inherited 
but  there  is  danger  of  infection  of  the  child  at  birth  and  the 
deleterious  effects  upon  the  sex  organs  of  the  parent  may  be 
serious.  The  case  against  alcohol  is  not  as  clear  for  the  evi- 
dence of  physical  or  mental  inferiority  in  the  children  of 
alcoholics  is  conflicting.  Possibly  none  of  these  substances 
are  true  race  poisons  as  the  offspring  which  do  survive  do  not 
appear  to  pass  on  the  defects  to  the  next  generation.  But  cer- 
tainly a  belief  in  the  noninheritanee  of  acquired  character- 
istics is  not  an  argument  for  intemperance  and  incontinence. 

One  may  ask,  however,  whether  this  does  not  end  the  paren- 
tal obligation  to  exercise  proper  control  over  the  temper  and 
the  nervous  system  generally.  The  answer  would  be  that 
faulty  hygiene  in  these  respects  will  injuriously  affect  the 
general  vitality  of  the  individual  and,  what  is  more  impor- 
tant, the  environment  of  the  children.  Furthermore  if  the  in- 
dividual is  a  confirmed  neurasthenic  perhaj)s  he  ought  to  con- 
sider the  inadvisibility  of  rearing  children. 

PRENATAL  CARE 

But  it  is  not  enough  that  a  child  should  have  a  good  in- 
heritance ;  if  it  is  to  be  well  born  it  must  live  under  proper 
conditions  during  the  fetal  period  and  if  it  is  to  start  life 
without  physical  handicaps  it  must  be  given  special  and 
proper  care  during  its  early  infancy  and  childhood.  The 
great  need  is  that  mothers  should  realize  that  childbirth  is  an 
exceedingly  important  affair  which  involves  the  future  health 
(if   two    individuals    and    tliat    1he    expectant    inothei-    shcuild 


96  HYGIENE:     DENTAL   AND   GENERAL 

early  realize  her  condition  and  seek  the  advice  of  the  best 
physician  available.*  In  many  centers  of  population  the 
health  departments  carry  out  a  proper  function  in  providing 
health  centers  where  advice  upon  these  subjects  can  be  se- 
cured. The  physician  has  no  cause  to  object  to  this  arrange- 
ment since  the  woman  who  is  able  to  pay  for  the  services  of 
her  own  physician  will  prefer  to  do  so,  and  certainly  physi- 
cians are  willing  to  let  someone  else  take  care  of  their  charity 
cases  or  prepare  such  cases  for  delivery. 

We  may  enumerate  some  of  the  reasons  why  it  is  important 
for  the  prospective  mother  to  consult  her  physician  or  one  of 
the  health  centers  when,  by  the  absence  of  menstruation  or 
other  signs  of  pregnancy,  she  realizes  her  condition.  She 
should  know  that  the  heavy  tax  upon  the  system  and  the  ex- 
treme muscular  energy  required  at  childbirth  make  it  in  re- 
ality "an  athletic  event"  and  she  must  begin  training  for 
this,  the  most  important  event  in  her  life.  She  should  have 
a  thorough  physical  examination  to  see  whether  there  are  any 
organic  defects.  This  should  include  an  examination  of  the 
heart,  the  urine,  lungs,  and  blood.  Many  bodily  defects,  if 
discovered  at  this  time,  can  be  corrected  before  childbirth 
and  perhaps  the  life  of  both  mother  and  infant  saved  thereby. 

The  teeth  should  be  given  careful  examination  because 
their  decay  during  pregnancy  is  extremely  rapid.  For  this 
decay  two  probable  causes  have  been  suggested;  the  use  of 
calcium  salts  in  building  bone  tissue  for  the  infant  and  the 
probable  increase  in  acidity  in  the  mouth  of  the  expectant 
mother.  Repair  work  should  put  the  teeth  in  perfect  con- 
dition early  in  pregnancy  and  they  should  be  given  daily  at- 
tention. 

If  it  is  the  first  pregnancy  the  physician  who  is  to  take  care 
of  the  ease  will  also  measure  the  pelvis  to  see  whether  there  is 
danger  of  obstruction  to  labor  because  of  the  small  size  or  ab- 

*Iviteratiire  on  prenatal  hygiene  can  be  secured  from  any  State  Department 
of  Health  or  from  the  U.   S.  Public  Health  Service. 


HYGIENE    OP    REPRODUCTION  97 

normal  shape  of  the  pelvic  canal.  He  will  also  be  on  the 
watch  for  albuminuria  and  eclampsia,  and  will  require  the 
patient  to  submit  a  sample  of  urine  at  least  once  a  month. 
The  latter  condition  which  in  its  later  manifestations  pro- 
duces convulsions  and  unconsciousness  may  be  largely  avoided, 
even  among  women  bearing  the  first  child,  by  early  detection 
and  proper  hygiene.  Patent  medicines  advertised  to  make 
childbirth  safe,  easy  and  painless  are  frauds,  and  cannot  be 
substituted  for  the  services  of  a  physician. 

The  woman  should  realize  that  a  double  burden  is  placed 
upon  her  vitality.  She  must  eat  for  the  child  and  excrete  the 
waste  products  produced  by  the  metabolism  of  its  body.  It 
is  probably  the  presence  of  some  of  these  waste  products  which 
causes  morning  sickness  with  other  systemic  disturbances. 
Following  is  a  list  of  directions  prepared  by  Dr.  Austin 
Brandt,  a  prominent  obstetrician  of  Boston,  for  the  use  of  his 
patients. 

DIRECTIONS  DURING  PREGNANCY 

Be  careful  to  bring  or  send,  a  clean  specimen  of  the  urine  every 
week.  Have  your  name  and  address  on  the  bottle.  Even  if  feeling 
perfectly  well,  come  to  the  office  at  least  once  a  month. 

If  possible,  drink  each  day  six  glasses  of  water  between  meals — one 
the  first  thing  in  the  morning — two  during  the  forenoon;  two  during 
the  afternoon;   and  one  just  before  retiring. 

Be  careful  to  have  the  bowels  move  regularly  each  day;  and  report 
any  inability  in  this  direction. 

Keep  the  skin  healthy  by  frequent  bathing.  Use  only  the  shower 
bath  during  the  last  three  weeks. 

r'or  exercise,  walking  is  the  best.  Walk  from  one  to  two  miles  each 
day.     Avoid  lawn-tennis,  horseback  riding,  and  fast  or  rough  motoring. 

Bathe  the  nipples  night  and  morning  with  the  solution  prescribed. 

Wear  loose  clothing,  capable  of  being  adjusted  to  the  increasing  size 
of  the  abdomen.  There  is  no  objection  to  loose  fitting  corsets.  Do  not 
wear  circular  garters. 

Report  headache,  vomiting  (especiallj  after  the  middle  of  pregnancy)  ; 
any  marked  swelling  of  limbs  or  face;  any  disturbance  of  vision;  any 
bleeding  or  escape  of  water;  any  pain  with  regular  recurrences. 


98  HYGIENE:     DENTAL    AND    GENERAL 

Standards  for  Maternity  Care. — ^The  responsibility  of  the 
community  or  the  state  in  providing  the  proper  facilities  for 
suitable  maternity  care  is  set  forth  in  the  following  list  of 
requirements  prepared  by  the  Children's  Bureau  of  the  U.  S. 
Department  of  Labor  as  part  of  a  set  of  minimum  standards 
for  child  welfare. 

MATEENITY 

•  1.  Maternity  or  prenatal  centers,  sufficient  to  provide  for  all  cases 
not  receiving  prenatal  supervision  from  private  physicians.  The  work 
of  such  a  center  should  include : 

(a)  Complete  physical  examination  by  physician  as  early  in  pregnancy 
as  possible,  including  pelvic  measurements,  examination  of  heart,  lungs, 
abdomen,  and  urine,  and  the  taking  of  blood  pressure;  internal  exami- 
nation before  seventh  month  in  primipara;  examination  of  uiine  every 
four  weeks  during  early  months,  at  least  every  two  weeks  after  six 
months,  and  more  frequently  if  indicated;  Wassermann  test  whenever 
possible,  especially  when  indicated  by  symptoms. 

(b)  Instruction  in  hygiene  of  maternity  and  supervision  throughout 
pregnancy,  through  at  least  monthly  visits  to  maternity  centers  until 
end  of  sixth  month,  and  every  two  weeks  thereafter.  Literature  to  be 
given  mother  to  acquaint  her  with  the  principles  of  infant  hygiene. 

(c)  Employment  of  sufficient  number  of  public-health  nurses  to  do 
home  visiting  and  to  give  instruction  to  expectant  mothers  in  hygiene  of 
pregnancy  and  early  infancy;  to  make  visits  and  to  care  for  patient  in 
puerperium;  and  to  see  that  every  infant  is  referred  to  a  children's 
health  center. 

(d)  Confinement  at  home  by  a  physician  or  a  properly  trained  and 
qualified  attendant,  or  in  a  hospital. 

(e)  Nursing  service  at  home  at  the  time  of  confinement  and  during 
the  lying-in  period,  or  hospital  care. 

(f)  Daily  visits  for  five  days,  ajid  at  least  two  other  visits  during 
second  week  by  physician  or  nurse  from  maternity  center. 

(g)  At  least  ten  days'  rest  in  bed  after  a  normal  delivery,  with  suffi- 
cient household  service  for  four  to  six  weeks  to  allow  mother  to  recu- 
perate. 

(h)  Examination  by  physician  six  weeks  after  delivery  before  dis- 
charging patient. 

(Where  these  centers  have  not  yet  been  established,  or  where  their 
immediate  establishment  is  impracticable,  as  many  as  possible  of  these 
provisions  here  enumerated  should  be  carried  out  by  the  community 
nurse,  under  the  direction  of  the  health  officer  or  local  physician.) 


HYGIENE   OP    REPRODUCTION  99 

2.  Clinics,  such  as  dental  clinics  and  venereal  clinics,  for  needed 
treatment  during  pregnancy. 

3.  Maternity  hospitals,  or  maternity  wards  in  general  hospitals,  suffi- 
cient to  provide  care  in  all  complicated  cases  and  for  all  women  wish- 
ing hospital  care;  free  or  part-payment  obstetrical  care  to  be  provided 
in  every  necessitous  case  at  home  or  in  a  hospital. 

4.  All  midwives  to  be  required  by  law  to  show  adequate  training,  and 
to  be  licensed  and  supervised. 

5.  Adequate  income  to  allow  the  mother  to  remain  in  the  home  through 
the  nursing  period. 

6.  Education  of  general  public  as  to  problems  j)resented  by  maternal 
and  infant  mortality  and  their  solution. 

Statistics  show  the  importance  of  better  maternity  care. 
The  United  States  ranks  fourteenth  in  a  list  of  sixteen  leading 
countries  in  its  rate  of  maternal  mortality.  To  quote  from  a 
special  report  of  the  Children's  Bureau: 

Out  of  the  16,000  women  who  die  (annually  at  childbirth)  about 
7,500  die  from  diseases  which  are  now  to  a  great  extent  preventable  or 
curable. 

In  1913  childbirth  caused  more  deaths  among  women  15  to  44  years 
old  than  any  other  disease  except  tuberculosis;  it  caused  in  the  same 
year  among  the  same  age  group  between  three  and  four  times  as  many 
deaths  as  typhoid  fever. 

During  the  13  years  from  1900  to  1913  the  typhoid  rate  has  been 
cut  in  half,  the  tuberculosis  rate  markedly  reduced,  the  diphtheria  rate 
reduced  more  than  one-half.  In  other  countries  there  has  been  a  de- 
crease in  the  death  rate  from  childbirth,  but  in  the  United  States  * 
*  *  the  new  figTires  now  published  by  the  Census  Bureau  for  the 
year  1916  (16.3  per  100,000  population)  indicated  that  since  1900 
no  decrease  in  maternal  deaths  had  yet  taken  place.  And  physicians 
remind  us  that  the  women  who  die  in  childbirth  are  few  beside  those 
who  sulfer  preventable  illness  or  a  lifelong  impairment  of  health. 

The  loss  involved  is  immeasurable.  It  does  not  stop  with  the  loss 
of  vigor  and  efficiency  in  the  mother.  It  extends,  in  general,  to  the 
well-being  of  her  children;  and  in  particular  to  the  motherless  infant 
who  faces  a  peculiarly  hazardous  existence.  For  example,  in  two  of 
the  cities  included  by  the  Cliildren 's  Bureau  in  its  study  of  infant 
mortality,  the  mortality  rate  among  babies  whose  mothers  died  dur- 
ing the  year  following  birth  is  compared  with  the  rate  for  all  the 
babies  in  the  city.     In  Watcrbuiy  the  rate  among  the  motherless  babies 


100  HYGIENE:     DENTAL   AND    GENERAL 

is  three   times   the   avci'age  for  the   city;    in  Baltimore,   five   times   the 
average  for  the  city. 

Our  enemies  are  chiefly  ignorance  and  poverty — from  a  community 
point  of  view  perhaps  mostly  ignorance. 

INFANT  CARE 

The  birth  and  the  early  days  of  infant  life  should  represent 
the  important  culmination  of  all  these  weeks  of  care  and  it 
goes  without  saying  that  the  best  obstetrical  services  should  be 
secured  and  that  the  mother  should  be  given  an  opportunity 
to  rest  after  this  ordeal.  During  the  prenatal  period  and  the 
early  days  of  infancy  the  district  or  public  health  nurse  is 
an  invaluable  asset  to  the  community  and  her  activities  under 
a  properly  managed  health  department  have  always  shown 
a  saving  of  mother  and  infant  lives. 

It  is  exceedingly  important  that  the  mother  should  learn 
from  her  physician,  from  the  health  center  or  from  literature 
on  infant  hygiene,  the  essentials  in  caring  for  her  baby.  She 
should  know  that  four  bottle-fed  babies  die  to  one  that  is  fed 
by  its  mother  and  that  apart  from  the  greater  danger  of 
disease  in  artificial  feeding,  there  is  surely  greater  strength 
and  vitality  among  babies  who  are  breast-fed.  She  should 
eat  only  foods  which  agree  with  her  or  otherwise  the  quality 
of  her  milk  may  change;  and  if  possible  she  should  avoid 
weaning  the  baby  in  the  hottest  weather  when  intestinal  dis- 
eases among  children  are  most  common.  The  baby's  clothing 
should  not  be  too  warm  or  too  tight.  It  needs  fresh  air  and 
rest  and  not  continual  movement  by  being  tossed  in  the  air. 
The  house  must  be  kept  clean.  The  daily  bath  should  be 
properly  administered;  during  the  first  three  months  the 
water  should  be  about  body  temperature. 

All  these  and  many  other  things  are  highly  important  to 
the  welfare  of  the  infant  and  are  mentioned  here  only  to  re- 
inforce the  statement  that  the  importance  of  childbirth  de- 
mands that  the  mother  should  properly  inform  herself  through 


HYGIENE    OF    REPRODUCTION  101 

the  aid  of  her  physician  or  the  organized  health  department 
of  her  state  or  city. 

The  following  quotation  from  a  pamphlet  on  Breast  Feed- 
ing Her  Baby  in  the  "Keep  Well  Series"  of  pamphlets  issued 
by  the  U.  S.  Public  Health  Service,  is  an  example  of  the  ex- 
cellent, concise  and  specific  health  literature  available  from 
government  agencies. 

Of  every  100  bottle-fed  babies  25  die  in  the  first  year  of  life;  of 
every  100  breast-fed  babies  only  6  die  in  the  first  year  of  life. 

Nearly  every  mother  can  nurse  her  baby  during  the  first  three  or 
fouj-  months  of  its  life,  and  if  she  can  nurse  it  for  ten  months  so  much 
the  better. 

There  may  be  an  abundant  supply  of  milk  after  the  first  few  weeks, 
even  if  there  is  but  little  at  first;  the  act  of  nursing  causes  the  milk 
to  come  into  the  breasts  and  increases  the  supply.  It  is  very  important 
that  the  baby  nurse  regularly. 

In  case  the  baby  is  not  getting  enough  milk,  the  quantity  lacking 
should  be  made  up  by  properly  prepared,  safe  cow's  milk.  Let  a 
physician  decide  this.  There  may  be  only  a  temporary  shortage  on 
the  mother's  part,  and  with  suitable  care  the  milk  will  probably  in- 
crease so  that  the  breast  supply  will  eventually  become  sufficient. 

Peace  of  mind  is  necessary  for  the  nursing  mother;  she  should  have 
no  worries;  she  should  not  get  overtired.  She  should  eat  freely  of 
her  customary  diet.  The  total  quantity  of  fluids  taken  by  her  in  24 
hours  should  not  be  less  than  2  quarts;  more  in  hot  weather.  Stuffing, 
however,  is  unnecessary  and  undesirable. 

Tuberculosis  in  the  mother  is  practically  the  only  disease  that  always 
forbids  nursing.  Paleness,  nervousness,  fatigue,  pains  in  the  back  and 
chest,  or  the  return  of  the  monthly  sickness  are  not  sufficient  reasons 
for  weaning,  but  when  these  symptoms  are  present  or  pregnancy  ensues 
a  physician  should  be   consulted  at  once. 

Shortly  after  birth,  boiled  water,  without  sugar,  may  be  given  to 
tlio  baby  at  regular  intervals  until  the  mother 's  milk  supply  is  estab- 
lif-'hed.  The  baby,  however,  should  be  put  to  the  breast  at  stated 
times,  as  often  as  the  mother  's  condition  permits. 

It  is  always  Avise  to  make  nursing  as  easy  as  possible  for  tlie  mother 
and  to  give  her  opportunities  for  rest.  Therefore,  the  sooner  the  baby 
i:}  satisfied  and  gaining  on  three-hour  or  even  four-hour  intervals  the 
better. 

Convenient  liours  for  nursing   tlic  bal)y  are  as  follows: 

1,  Seven  nursings  in  24  hours. — 6  a.  m.,  12  noon,  3  p.  ni.,  6  p.  m.,  8 
or  10  p.  m.,  and  once  during  the  night. 


102  HYGIENE:     DENTAL   AND   GENERAL 

2.  Six  nursings  in  24  hours. — 6  a.  m.,  9  a.  m.,  12  noon,  3  p.  m.,  6 
p.  ni.,  and  at  the  mother's  bedtime j  or  at  6  a.  m.,  10  a.  m.,  2  p.  m.,  6 
p.  m.,  10  p.  m.,  and  one  during  the  night. 

3.  Five  nursings  in  24  hours. — 6  a.  m.,  10  a.  m.,  2  p.  m.,  6  p.  m.,  10 
p.  m.,  or  later. 

The  baby  should  be  offered  cooled  boiled  water  between  feedings, 
especially  during  hot  weather. 

The  length  of  time  for  a  nursing  varies  with  the  infant  and  with 
the  breast.  The  average  infant  rarely  nurses  longer  than  fifteen  min- 
utes. The  important  point  is  to  satisfy  the  baby.  If  there  is  any 
doubt,  let  it  nurse  longer,  but  not  more  than  twenty  minutes.  If  it 
is  not  satisfied  after  twenty  minutes,  consult  a  physician. 

It  is  customary  to  nurse  only  with  one  breast  at  each  feeding,  and 
to  use  them  alternately.  If,  however,  the  baby  does  not  get  enough 
from  one  breast,  give  it  both. 

It  is  important  to  keep  the  nipples  clean;  they  should  be  washed 
before  each  nursing.  Caked  breast,  or  cracked  nipples,  although  they 
may  be  harmful  to  the  mother,  do  not  make  the  milk  poisonous  for 
the  baby.  In  both  instances  consult  a  physician,  for  a  breast  abscess 
may  result  if  the  condition  is  not  attended  to.  The  baby  should  usually 
be  completely  weaned  at  the  end  of  the  first  year.  Up  to  this  time 
breast  milk  should  be  given  to  the  baby  as  long  as  it  thrives.  It  is 
better,  when  possible,  to  continue  nursing  thi-ough  the  summer  and 
to  wean  in  the  fall,  but  if  the  year  has  not  been  completed  in  the  spring, 
ic  is  better  to  wean  in  the  summer  than  in  the  spring. 

Do  not  wean  the  baby  suddenly;  it  should  be  done  gradually  by 
replacing  one  breast  feeding  at  a  time  with  a  bottle  feeding.  Several 
v/eeks  are  required  for  weaning. 

It  is  dangerous  to  wean  a  young  baby.  It  should  not  be  done  for 
the  convenience  of  the  mother  and  should  never  be  done  without  the 
advice  of  a  physician. 

When  the  mother's  milk  is  diminishing  it  is  advisable  to  make  up 
the  lack  with  properly  modified  cow's  milk.  This  may  be  done  either 
by  following  one  or  more  breast  feedings  with  enough  modified  milk 
to  satisfy  the  baby  or  by  giving  one  or  more  full  bottle  feedings  in 
place  of  a  like  number  of  breast  feedings. 

The  flow  of  breast  milk  tends  to  diminish  when  the  baby  nurses 
less  than  five  times  in  24  hours.  When  the  baby  is  being  nursed  once 
every  four  hours  and  is  not  satisfied  it  is  better  to  replace  a  nursing 
with  the  bottle.  If,  however,  shorter  intervals  and  more  feedings  are 
being  used,  a  bottle  feeding  may  take  the  place  of  a  nursing  without 
so  much  danger  of  decreasing  the  supply  of  breast  milk.  Most  babies 
need  additional  food  after  the  seventh  month. 


HYGIENE    OF    REPRODUCTION  103 

The  Obligation  of  the  Community  to  the  Infant  and  the 
Preschool  Child. — The  statistics  of  1916  shoAv  that  more 
than  75,000  babies  in  the  United  States  died  before  they  had 
completed  their  first  month  of  life.  From  the  latest  available 
statistics  the  average  number  of  deaths  under  one  year  of  age 
per  thousand  births  in  the  United  States  is  94).  But  there  is 
ample  room  for  improvement  as  shown  by  comparing  this 
figure  with  the  following  rates  for  other  countries :  New  Zea- 
land, 48 ;  Australia,  56 ;  Norway,  68  ;  Sweden,  70 ;  Switzerland, 
78 ;  The  Netherlands,  85 ;  Ireland,  88 ;  Denmark,  95 ;  England 
and  Wales,  96 ;  Scotland,  107. 

England  showed  us  what  it  is  possible  to  do  by  actually 
reducing  the  infant  mortality  rate  to  the  lowest  point  in  her 
history  while  the  world  war  was  being  carried  on.  This  was 
accomplished  by  providing  for  the  compulsory  notification  of 
births  within  thirty-six  hours,  government  aid  for  local  ma- 
ternity and  infant  welfare  work  amounting  to  not  more  than 
50  per  cent  of  the  approved  expenditure,  publicity  explaining 
the  government  plan  with  its  details  for  antenatal,  natal,  and 
postnatal  work,  and  a  great  increase  in  the  number  of  health 
visitors.  The  number  of  these  visitors  was  increased  from 
600  in  1914  to  1,024  in  1917  and  the  Board  recommends  that 
there  should  be  one  to  every  400  births.  The  number  of 
Avelfare  centers  in  England  and  Wales  increased  from  850  in 
1917  to  1278  in  1918. 

The  duty  of  our  own  communities  is  set  forth  by  the  Chil- 
dren's Bureau  in  the  following  set  of  standards  for  Child 
Welfare  relating  to  infants  and  preschool  children. 

1.  Complete  birth  registration  by  adequate  legislation  requiring  re- 
porting within  three  clays  after  birth. 

2.  Prevention  of  infantile  blindness  by  making  and  enforcing  ade- 
quate laws  for  treatment  of  eyes  of  every  infant  at  birth  and  super- 
vision of  all  positive  cases. 

3.  Sufficient  number  of  children's  health  centers  to  give  health  iu- 
straction  under  medical  supervision  for  all  infants  and  children  not 
under  the  care  of  a  private  physician,  and  to  give  instruction  in  breast 
feeding  and  in  care  and  feeding  of  children  to  mothers,  at  least  once 


104  HYGIENE:     DENTAL   AND   GENERAL 

a  month  throughout  the  first  year,  and  at  regular  intervals  throughout 
preschool  age.     This  center  to  include  a  nutrition  and  dental  clinic. 

4.  Children's  health  center  to  provide  or  to  cooperate  with  sufficient 
number  of  public-health  nurses  to  make  home  visits  to  all  infants  and 
children  of  preschool  age  needing  care — one  public-health  nurse  for 
average  general  population  of  2,000.  Visits  to  the  home  are  for  the 
purpose   of  instructing  the   mother   in — 

(a)  Value  of  breast  feeding. 

(b)  Technic  of  nursing. 

(c)  Technic  of  bath,  sleep,  clothing,  ventilation,  and  general  care 
of  the  baby,  with  demonstrations. 

(d)  Preparation  and  technic  of   artificial  feeding. 

(e)  Dietary  essentials  and  selection  of  food  for  the  infant  and  for 
older  children. 

(f)  Prevention   of   disease  in  children. 

5.  Dental  clinics;  eye,  ear,  nose,  and  throat  clinics;  venereal  and 
other  clinics  for  the  treatment  of  defects  and  disease. 

6.  Children's  hospitals,  or  beds  in  general  hospitals,  or  provision 
for  medical  and  nursing  care  at  home,  sufficient  to  care  for  all  sick 
infants  and  young  children. 

7.  State  licensing  and  supervision  of  child-caring  institutions  or 
homes  in  which  infants  or  young  children  are  eared  for. 

8.  General  educational  work  in  prevention  of  communicable  disease 
and  in  hygiene  and  feeding  of  infants  and  young  children. 

SEX  HYGIENE 

A  properly  arranged  sex  life  cannot  be  insured  by  preach- 
ing fear  and  the  consequences  of  immorality,  but  certainly 
the  proper  basis  for  a  normal  sex  life  in  the  developing  child 
is  adequate  knowledge.  The  old-style  false  modesty  and  inno- 
cence has  been  shown  in  many  cases  to  be  not  only  useless  but 
dangerous  and  pernicious. 

Sex  Education. — Instruction  in  sex  hygiene  may  be  di- 
vided into  three  parts.  Beginning  at  the  age  of  three  years 
the  child  is  likely  to  ask  questions  as  to  whence  it  came.  It 
should  be  given  a  truthful  answer  to  its  questions  but  no  more. 
Old  stories  about  the  stork  are  not  to  be  used,  but  on  the 
other  hand,  this  is  not  the  time  and  place  to  teach  sex  hygiene 
and  prophylaxis.     This  inquisitiveness  dies  out  to  a  large  ex- 


HYGIENE    OF    REPRODUCTION  105 

tent  at  abont  the  age  of  five.  By  this  time  the  child  should 
learn  that  questions  concerning  these  subjects  are  to  be 
brought  to  the  parent. 

The  second  stage  of  instruction  is  just  before  the  age  of 
puberty — twelfth  to  fourteenth  years.  At  this  time  the  child 
should  be  given  certain  information  about  the  changes  which 
it  is  soon  to  undergo.  The  instruction  should  be  brief,  per- 
sonal, and  individual.  This  is  a  task  for  the  parent,  doctor, 
or  friend,  but  not  for  the  public  school.  The  story  is  brief 
and  caji  be  told  in  a  few  minutes.  It  should  not  fire  the  imagi- 
nation but  should  warn  against  abuse  and  explain  how  it  is 
that  continence  is  entirely  compatible  with  health.  Such  in- 
struction cements  the  friendship  of  the  child. 

The  third  stage  of  instruction  is  to  be  given  to  young  men 
and  women  at  the  age  of  sixteen  to  eighteen  years,  and  con- 
cerns chiefly  information  regarding  the  venereal  peril.  Such 
a  book  as  The  Three  Gifts  of  Life  by  Nellie  M.  Smith  (Dodd, 
Mead  &  Co.,  New  York,  1918)  presents  the  story  of  sex  to 
girls  in  a  splendid  and  interesting  way  and  may  well  be  used 
to  precede  such  a  talk.  Here  again  high  school  biology  is  not 
the  place  for  the  subject  to  be  taught. 

Fear  alone  is  not  a  deterrent,  but  an  actual  knowledge  of 
the  dangers  in  the  path  and  a  true  picture  of  the  beauty  of 
virtue,  appealing  to  the  boy's  love  for  sister  and  mother  with 
a  consideration  of  the  obligations  to  the  future  wife,  will  go 
far  to  pave  the  way  for  proper  living.  We  may  deplore  the 
double  standard  of  morals,  but  in  changing  it,  we  must  see 
that  the  boy  accepts  the  standard  of  the  girl  and  that  we 
preach  equal  restraint,  not  equal  liberty,  for  belief  in  the 
chastity  of  Avomcn  is  a  most  important  restraining  influence 
in  the  boy  and  young  man.  It  is  hardly  necessary  to  add  that 
a  vigorous  physical  life,  helpful  social  surroundings  and  ab- 
stinence from  alcohol  are  most  important  factors. 

The  third  stage  of  sex  instruction  has  recently  been  made 
much  easier  by  the  activities  of  the  Federal  and  State  depart- 
ments of  health  which  have  established  special  bureaus  for  the 


106  HYGIENE:     DENTAL   AND   GENERAL 

control  of  venereal  diseases  and  have  made  available  moving 
pictures  and  pamphlets  for  information  on  this  subject.  The 
motion  pictures  prepared  and  shown  under  the  auspices  of 
the  government  and  preceded  by  a  medical  talk  from  an  of- 
ficial of  the  health  department  are  very  helpful.  The  boy  or 
girl  between  fifteen  and  nineteen  however  should  be  accom- 
panied to  these  pictures  by  the  proper  parent.  It  is  certainly 
undesirable  that  these  pictures  should  be  shown  for  profit  and 
without  proper  supervision  and  accompanying  medical  in- 
struction, for  then  the  mind  of  the  boy  or  girl  is  centered 
upon  the  suggestive  elements  and  not  upon  the  medical  facts. 
Public  sentiment  shoud  prevent  the  improper  use  of  these 
films. 

Summary. — In  The  Child's  Ten  Commandments  to  Parents, 
written  some  time  ago  for  the  American  Journal  of  Public 
Health,  I  have  summarized  many  of  the  obligations  mentioned 
above : 

The  Child's  Ten  Commandments  To  Parents 

And  a  new  voice  said  to  the  people, 

I  am  the  generation  yet  unborn  who  by  being  well  born  and 
properly  cared  for  shall  lead  the  race  out  of  the  bondage  of 
disease  to  a  healthier,  better,  and  happier  life. 

Thou  shalt  have  no  temporal  gods  before  me. 

Thou  shalt  not  bow  down  thyself  before  false  images  of 
temporal  pleasures  or  become  bound  by  overwork  or  by  in- 
temperance in  thy  food,  thy  drink,  or  thy  habits,  for  thy  God 
is  a  righteous  God  and  visiteth  these  sins  in  the  form  of  phys- 
ical weakness  upon  thy  children. 

Thou  shalt  not  take  my  name  in  vain  or  think  lightly  of 
me  in  thy  younger  days  for  thou  must  begin  when  a  boy  or 
girl  to  prepare  for  my  coming,  by  building  a  strong  body  and 
keeping  it  free  from  harmful  substances  and  the  taint  of 
disease. 

Kemember  the  pre-natal  days  and  keep  them  properly. 
Other  days  shalt  thou  do  hard  labor  if  need  be,  but  these  are 


HYGIENE    OF   REPRODUCTION  107 

the  months  that  are  mine,  and  thou  shalt  seek  advice  of  thy 
physician  and  so  conduct  thy  life  and  that  of  thy  family  that 
I  may  become  strong  and  not  afflicted  in  these  days  of  my 
coming. 

Honor  thy  sons  and  thy  daughters  that  our  days  may  be 
long  upon  the  earth ;  when  we  are  babes  give  us  the  food  which 
nature  intended  us  to  have  and  see  that  such  hygienic  meas- 
ures prevail  in  thy  house  and  in  the  community  where  thou 
livest  that  we  shall  not  be  menaced  by  disease. 

Thou  shalt  not  kill  our  confidence  in  thee  by  telling  us 
lies  about  ourselves,  and  when  at  an  early  age  we  begin  to 
ask  from  whence  we  came,  thou  shalt  answer  the  questions 
truthfully  and  volunteer  no  further  information. 

Thou  shalt  not  make  it  easy  for  us  to  commit  sexual  ex- 
cesses by  neglecting  to  tell  us  at  the  time  of  puberty  what 
changes  are  to  come  upon  our  physical  beings,  and  at  the  time 
of  early  manhood  or  womanhood  thou  or  thy  trusted  friend 
shall  explain  to  us  individually  the  nature  of  those  diseases 
which  may  inflict  suffering  upon  us  and  upon  those  w^e  love, 
explaining  also  the  rules  of  personal  hygiene,  which  will  en- 
able us  to  avoid  all  excesses  that  would  make  us  in  our  gener- 
ation unflt  for  parenthood. 

Thou  shalt  not  steal  our  peace  of  mind  by  failing  to  inform 
thyself  and  consult  with  us  frankly  upon  problems  involving 
the  proper  development  of  the  body,  the  mind,  or  the  social 
and  religious  conscience. 

Thou  shalt  not  bear  false  witness  to  what  thou  wouldst 
have  us  believe  by  leading  a  life  which  is  unhygienic,  empty 
of  serious  thought  or  immoral. 

Thou  shalt  not  covet  ease  for  thyself  or  thy  children  there- 
by forgetting  the  duties  of  every  person  as  a  citizen  and  a 
neighbor. 


CHAPTER  VI 

THE  NEW  SCIENCE  OF  DISEASE  PREVENTION 

Communicable  Diseases. — Thus  far  we  have  considered  the 
normal  functioning  of  the  body  in  the  endeavor  to  point  the 
way  toward  the  normal  conduct  of  life  and  the  avoidance  of 
diseases  which  arise  from  some  derangement  of  the  body 
mechanism  from  within.  There  is  another  group  of  diseases, 
those  which  arise  from  without  the  body,  and  a  study  of  death 
statistics  shows  that  these  two  groups  of  diseases  are  of  about 
equal  importance  as  causes  of  death.  We  are  now  to  turn 
our  attention  to  diseases  which  are  comparable  to  the  troubles 
with  a  machine  arising  from  the  entrance  of  foreign  bodies. 
By  the  recent  and  rapid  development  of  preventive  medicine, 
preventive  sanitation,  and  preventive  hygiene  the  number  of 
deaths  from  this  group  of  diseases  is  being  rapidly  reduced, 
and  it  is  here  that  the  greatest  opportunity  for  prevention 
lies.  In  the  body,  as  in  the  machine,  it  is  possible  to  prevent 
these  injuries  arising  from  without  while  the  results  of  wear 
and  tear  will  eventually  make  themselves  felt. 

Early  Theories  of  Disease. — It  is  difficult  to  realize  that  our 
knowledge  of  the  cause  of  communicable  disease  does  not  date 
back  of  our  own  Civil  War  and  that  many  people  now  living 
can  distinctly  remember  the  days  when  germs  were  unknown. 
Previous  to  this  time  the  world  had  entertained  A^ague  notions 
as  to  the  nature  of  these  maladies,  including  the  early  con- 
ceptions of  primitive  man,  the  doctrines  of  Hippocrates  and 
later  the  doctrines  of  Sydenham. 

The  tendency  of  primitive  man  to  personify  all  natural 
phenomena  led  to  the  earliest  conception  of  disease  as  the 
activity  of  individual  demons  and  according  to  this  demonic 

108 


NEW    SCIENCE    OF   DISEASE   PREVENTION  109 

theory  pain,  diseasp,  and  death  were  held  to  be  caused  by 
special  evil  spirits. 

From  Hippocrates  (460-359  B.C.)  came  the  theory  of  the 
four  humors  which  held  the  essential  elements  of  the  body 
to  be  phlegm,  blood,  yellow  bile,  and  black  bile  and  disease 
to  result  from  the  improper  balance  between  these  substances. 
Our  vocabulary  still  bears  testimony  to  this  belief  when  we 
speak  of  people  of  a  sanguine,  phlegmatic,  or  melancholy 
temperament.  And  this  is  not  surprising  since  the  theories 
of  Hippocrates  and  his  follower  Galen  dominated  medical 
thought  until  the  16th  century. 

We  cannot  be  detained  with  a  discussion  of  the  various  ad- 
vances in  thought  between  this  period  and  the  establishing 
of  our  present  knowledge  except  to  mention  the  work  of 
Thomas  Sydenham  (1644-1689)  who  asserted  that  "a,  disease 
is  nothing  more  than  an  effort  of  nature  to  restore  the  health 
of  the  patient  by  the  elimination  of  the  morbific  matter." 
In  his  belief  in  a  definite  substance,  the  materies  morlji,  as 
the  cause  of  the  disease,  the  "English  Hippocrates,"  as  Syden- 
ham has  been  called,  took  a  definite  step  in  advance  and  fore- 
shadowed the  scientific  recognition  of  infective  organisms  in 
the  classical  researches  of  Pasteur. 

Foreshadowings  of  the  Present  Theory. — Certain  other 
scientific  developments  preceded  the  work  of  Pasteur.  Most 
important  was  the  development  of  the  compound  microscope 
about  1835.  This  was  a  necessary  prerequisite  to  the  study 
of  infectious  disease,  as  well  as  to  the  development  of  cytolog- 
ical  and  histological  knowledge.  In  1837  the  Italian  investi- 
gator, Bassi,  discovered  that  a  contagious  disease  of  silk  worms 
known  as  muscardine  was  caused  by  a  parasitic  fungus  and 
only  two  years  later  (1839)  Schoenlein  showed  another  of 
these  mold-like  plants  to  be  the  cause  of  favus  or  honeycomb 
of  the  human  scalp.  Here  then  we  received  definite  infor- 
mation of  a  parasitic  plant  as  the  cause  of  a  human  disease. 

Fermentation  and  Disease. — It  was  in  1838  that  Cagniard 
de  Latour,  and  Schwann  in  studying  yeast  showed  that  alco- 


110  HYGIENE:     DENTAL   AND   GENERAL 

liolic  fermentation  is  caused  by  a  living  plant.  Their  theory 
that  this  plant  was  the  real  canse  of  the  fermentation  process 
was  at  first  disputed  and  was  only  thoroughly  and  finally 
established  by  Louis  Pasteur  (in  1857-1863)  who  went  still 
further  and  showed  that  the  "diseases"  of  beer  and  wine 
(abnormal  sour  and  bitter  tastes)  were  produced  by  micro- 
organisms other  than  ordinary  yeast.  These  had  invaded  the 
liquid  and  interfered  with  the  usual  alcoholic  fermentation 
by  producing  undesirable  fermentations  of  their  own. 

It  could  hardly  fail  to  occur  to  any  thoughtful  person  that  if  this 
were  true  for  certain  diseases  of  wine  and  beer,  it  might  well  be  true 
also  for  certain  diseases  of  animals  for  if  we  consider  step  by  step  the 
course  of  any  familiar  fermentation  and  then  do  the  same  for  any 
familiar  infectious  disease,  we  shall  discover  between  them  a  remark- 
able similarity.  Tor  this  purpose  we  may  take  the  fermentation  of 
ajople  juice,  or  cider,  and  smallpox.  The  juice  of  apples  is  heremeti- 
cally  sealed  and  kept  from  exposure  to  air  by  the  apple  skin.  In  the 
making  of  cider  this  skin  is  broken,  the  juice  is  pressed  out  and  of 
course  exposed  to  the  air,  to  dust,  to  the  press,  to  the  sides  of  the 
vessel  which  received  it,  to  the  strainer  through  which  it  passes,  etc. 
At  first,  and  for  some  time  the  juice  is  sweet,  insipid,  unfermented, 
but  after  some  time  it  is  plain  that  a  change  is  coming  over  it.  This 
change  is  called  the  '' working ''  or  active  fermentation  of  the  apple 
juice,  and  a  closer  examination  will  show  that  it  is  accompanied  by  a 
slight  rise  of  temperature  or  "heating"  (which  is  a  familiar  phe- 
nomenon in  many  fermentations),  as  well  as  by  obvious  chemical 
changes  resulting  in  the  evolution  of  gas  and  the  disappearance  of  sugar, 
in  place  of  which  alcohol  makes  its  appearance,  giving  to  the  whole 
process  the  name  of  ' '  alcoholic  fermentation. ' '  The  fermentation  of 
any  particular  portion  of  apple  juice,  however,  is  not  indefinitely  pro- 
longed. On  the  contrary,  after  a  comparatively  short  time,  thd  proc- 
ess comes  to  an  end,  the  evolution  of  gases  ceases,  and  rest  supervenes. 
Since  Pasteur's  classical  researches  we  know  that  what  has  really  hap- 
pened has  been  first,  the  seeding  of  the  apple  juice  by  (wild)  yeast; 
second,  the  slow  growth  of  this  during  the  quiescent  period;  tliird,  its 
active  growth  and  "working"  during  the  time  of  obvious  fermenta- 
tion; and  fourth,  its  gi-adual  cessation  of  activity  during  the  final 
period.  In  the  case  of  the  infectious  disease  known  as  smallpox  the 
history  is  usually  as  follows.  A  susceptible  patient  must  first  be  ex- 
posed to  the  disease,  perhaps  by  contact  with  a  person  already  affected, 
perhaps  with  clothing,  letters,  food  or  other  materials  handled  by  such 


NEW    SCIENCE    OF    DISEASE   PREVENTION 


111 


a  person.  After  such  exposure  there  is  for  a  time  no  marked  change; 
but  because  the  disease  has  been  shown  by  repeated  experience  to  be 
nevertheless  gradually  developing,  as  judged  by  the  result  and  certain 
obscure  premonitory  symptoms  afterward  recalled,  physicians  have  unan- 
imously agreed  to  name  this  the  period  of  incubation.  Sooner  or  later, 
headache,  malaise,  and  other  troubles  appear,  the  patient  becomes  se- 
riously ill,  a  physician  is  called  in,  a  rise  of  temperature  or  fever  is 
discovered,  the  eruption  and  other  marks  of  smallpox  appear,  and  tht 
patient  is  plainly  afEectsd  by  active  disease  accompanied  by  every  in- 
dication of  profound  disturbance  and  chemical  change.  But  at  last, 
if  death  does  not  supei-vene,  recovery  ensues,  and  the  patient  gradually 
becomes  free  from  the  disease  by  which  he  was  temporarily  overcome. 
We  may  add  that  the  barrel  of  apple  juice  can  undergo  the  alcoholic 
fermentation  once  only,  and  that  the  smallpox  patient  likewise,  as  a 
rule,  has  the  smallpox  omly  once.  If  now  we  tabulate  side  by  side  and 
in  order,  the  principal  phenomena  of  an  alcoholic  fermentation  such  as 
that  of  apple  juice,  and  those  of  an  infectious  disease  such  as  smallpox, 
we  shall  discover  a  remarkable  similarity  between  them. 


A    FEEMENTATION 

(Apple  juice) 

1.  Exposure    of    the   juice    to    air, 

dust,   etc. 

2.  Repose    and   then   slow   change. 

(Growth  of  the  ferment.) 

3.  Active  fermentation  or  "work- 

ing." Evolution  of  gas  bub- 
bles, change  of  sugar  to  al- 
cohol.    Rise   of   temperature. 

4.  Gradual  cessation  of  fermenta- 

tion. 

5.  No  further  liability  to  alcoholic 

fermentation. 


AN  INFECTIOUS  DISEASE 
(Smallpox) 

1.  Exposure  of  the  patient  to  in- 

fection. 

2.  Incubation.     (Slow    and    insid- 

ious progress  of  the  disease.) 

3.  Active    disease.     Eruption,    dis- 

turbance of  the  usual  func- 
tions. Rise  of  temperature 
or  fever. 

4.  Slow  convalescence    (or  death). 

5.  Immunity  to  smallpox. 


Tlie  striking  analogy  here  shown  suggests  something  more.  It  cer- 
tainly justifies  the  suspicion  of  relationship,  and  shows  well  the  natural 
fitness  of  the  term  "zymotic"  (fermentative)  for  that  class  of  diseases 
in  which  an  analogy  so  remarkable  is  manifest. — Sedgtoicl: 

Pasteur. — Just  as  Pasteur  had  finished  his  important 
studies  upon  the  nature  of  fermentation  in  wine  and  beer, 
thereby  opening  for  himself  a  broad  and  alluring  field  for 


112  HYGIENE:     DENTAL    AND    GENERAL 

further  research,  lie  was  urged  by  the  French  government  to 
undertake  the  study  of  a  disease  of  silkworms.  This  disease 
was  not  only  causing  an  annual  loss  of  100,000,000  francs  in 
France  but  it  was  spreading  rapidly  to  other  countries  so  that 
it  threatened  the  existence  of  the  silk  industry  in  all  parts  of 
the  world.  Pasteur  was  at  length  persuaded  to  attempt  a 
solution  of  this  problem  and  during  the  year  1865-1868  he 
proved  this  disease  (pebrine)  to  be  caused  by  a  particular 
germ  which  could  be  grown  by  itself  in  suitable  liquid.  He 
also  devised  a  method  by  which  the  eggs  could  be  hatched  and 
the  silkworms  reared  without  becoming  infected  with  this 
disease. 

He  had  now  definitely  established  the  fact  that  certain 
minute  plants  (bacteria)  were  capable  of  producing  partic- 
ular fermentations  or  souring  processes  in  beer  and  wine  and 
that  another  similar  organism  was  the  cause  of  an  infectious 
disease  which  had  killed  so  many  of  the  silkworms.  These 
bacteria  could  be  grown  by  themselves  and  separated  from 
other  organisms  in  a  suitable  liquid  and  would  always  produce 
their  own  particular  type  of  fermentation  or  disease  when 
put  back  in  the  proper  plajce.  The  foundations  for  the  science 
of  bacteriology  and  the  germ  theory  of  disease  were  thus  se- 
curely laid. 

Lister. — ^Development  from  this  point  was  rapid.  Sir 
Joseph  Lister,  reflecting  upon  the  significance  of  these  inves- 
tigations of  Pasteur,  concluded  that  many  wound  diseases 
were  probably  infectious  and  set  to  work  by  the  use  of  anti- 
septic dressings,  sprays,  etc.,  to  establish  his  thesis  which 
paved  the  way  for  the  modern  practice  of  sanitary  or  aseptic 
surgery. 

Koch  and  the  Development  of  Bacteriology. — Then  came 
the  startling  work  of  Robert  Koch  in  1875-78  who  firmly 
established  the  science  of  Bacteriology  by  his  researches  upon 
anthrax  and  other  diseases  and  by  the  adaptation  of  solid  cul- 
ture media,  prepared  from  gelatin  substances,  on  which  bac- 
teria could  be  readily  grown  and  isolated.     In  his  work  with 


NEW    SCIENCE    OF    DISEASE    PREVENTION  113 

anthrax  or  splenic  fever,  a  disease  then  very  common  among 
cattle  and  sheep,  and  occasionally  attacking  human  beings, 
he  found,  as  others  had  already  observed,  that  there  were 
minute  or  microscopic  rods  in  the  blood  of  animals  which  had 
died  from  this  disease.  These  minute  plants  he  removed  from 
the  tissues  and  planted  in  the  clear  liquid  which  constituted 
the  aqueous  humor  of  the  ox's  eye.  The  organism  grew  in 
this  liquid  from  which  minute  quantities  were  introduced  in- 
to fresh  aqueous  humor  several  times  in  succession  until  only 
the  remote  descendants  of  the  plants  first  used  were  left. 
When  these  were  introduced  into  healthy  animals  thy  pro- 
duced typical  anthrax.  In  other  words  the  chain  of  proof 
had  been  made  complete.  A  particular  germ  had  been  found 
in  animals  having  a  particular  disease,  it  had  been  isolated 
and  grown  by  itself  in  pure  cultures,  it  had  been  introduced 
into  healthy  animals  where  it  produced  disease  and  the  death 
of  the  animal,  after  which  it  could  be  recovered  from  the 
tissues.  These  four  steps  are  known  as  Koch's  rules  for  iden- 
tifying the  cause  of  a  disease. 

The  use  of  solid  media  in  1881  was  followed  by  the  dis- 
covery of  the  bacillus  of  tuberculosis  in  1882,  the  discovery 
of  the  cholera  vibrio  in  1883,  the  bacilli  of  diphtheria  and 
tetanus  (lock-jaw)  in  1884  and  so  on.  The  long  list  of  dis- 
eases for  which  the  causes  are  now  known  is  evidence  of  the 
rapid  growth  of  this  field.  AVe  find  diseases  caused  by  a  va- 
riety of  microorganisms  which  are  different  in  their  appear- 
ance, their  mode  of  living,  and  their  effect  upon  the  body. 
The  list  of  infective  organisms  includes  the  round,  the  rod- 
shaped,  and  the  spiral  type  of  bacteria,  fungous  or  mold-like 
plants  like  that  producing  honeycomb  of  the  scalp  and  also 
animal  parasites  like  those  producing  malaria  and  amebic 
dysentery. 

PREVENTIVE  MEDICINE 

Preventive  medicine  may  be  properly  limited  to  those  proc- 
esses by  which  the  individual  is  so  treated  as  to  become  im- 
mune to  particular  diseases,  in  other  words,  the  treatment  of 


il4  HYGIENE:     DENTAL   AND   GENERAL 

the  individual  to  prevent  disease.  We  must  look  to  Pasteur 
as  the  founder  of  this  new  science.  In  beginning  his  studies 
on  immunity  Pasteur  had  before  him  the  example  of  small- 
pox and  vaccination  which  had  been  developed  and  success- 
fully applied  without  knowledge  of  the  germ  theory  of 
disease.     Let  us  briefly  review  this  story. 

Smallpox  and  Vaccination. — ^As  early  as  1717  Lady  Mary 
Wortley  :]\Iontagu,  the  wife  of  the  British  ambassador  at  Con- 
stantinople wrote  to  friends  at  home  of  the  Turkish  custom 
of  "inoculating"  against  this  disease.  In  this  inoculation 
some  ' '  matter ' '  derived  from  the  pustle  of  a  smallpox  patient 
was  introduced  under  the  skin  of  a  healthy  person.  Such 
an  individual  by  choosing  inoculation  at  a  time  when  in  good 
physical  health,  had  a  mild  attack  of  the  disease  and  was  im- 
mune thereafter.  The  general  adoption  throughout  Europe 
of  this  strenuous  method  of  securing  immunity  speaks  for  the 
horror  in  which  the  disease  was  held.  Previous  to  that  time 
smallpox  was  the  great  scourge  and  destroyer  of  mankind, 
hardly  one  person  in  a  thousand  escaped  it  and  so  common 
was  it  that  nearly  everyone  took  the  disease  while  yet  a  child 
so  that  it  was  regarded  as  a  children's  disease. 

Then  came  the  wonderful  discovery  of  vaccine  by  Edward 
Jenner  in  1796.  Jenner  had  been  impressed  as  a  student  at 
Sudbury  by  the  remark  of  a  patient,  in  the  person  of  a  dairy 
maid,  who  said,  ' '  I  can  not  take  smallpox  because  I  have  had 
cowpox. "  Testing  this  belief  in  his  classical  experiments 
Jenner  transferred  the  vaccine  virus  from  the  eruption  upon 
the  hand  of  Sarah  Nelms, — a  dairy  maid  who  had  contracted 
cowpox  from  her  master's  cow  by  infection  through  a  scratch 
in  the  hand, — to  the  arm  of  James  Phipps,  a  boy  about  eight 
years  old.  This  successful  vaccination  was  followed  by  ex- 
posures to  see  that  it  provided  a  complete  immunity  against 
the  disease,  smallpox. 

Vaccination  experiments  were  made  elsewhere  and  in  Bos- 
ton, in  1802,  nineteen  boys  were  vaccinated  with  cowpox  in  an 
experiment  by  the  Board  of  Health.     Twelve  of  these  boys 


NEW   SCIENCE   OF    DISEASE   PKEVENTION  115 

were  later  inoculated  -with  smallpox  with  negative  results 
while  two  unvacciuated  boys  who  were  also  inoculated  with 
smallpox  virus  both  took  the  disease.  The  conclusion  of  the 
Board  of  Health  that  "cowpox  is  a  complete  security  against 
smallpox"  we  now  know  to  be  justified.  By  vaccination  this 
great  scourge  has  been  practically  eliminated.  Indeed,  so 
rare  has  it  become,  that  even  sensible,  though  unthinking, 
people  forget  the  horror  of  the  disease  and  give  ear  to  those 
who  oppose  vaccination  in  spite  of  the  fact  that  vaccination 
is  now  under  almost  perfect  control  and  is  the  only  sure  pre- 
vention for  smallpox. 

The  Immunity  in  Anthrax  and  Rabies. — But  it  remained 
for  Pasteur  to  develop  the  principle  of  immunity  and  to  apply 
it  to  other  diseases.  Applying  the  principle  of  germ  disease 
to  this  phenomenon  Pasteur  reasoned  that  if  the  infectious 
disease  is  a  struggle  between  a  man  and  a  microbe  it  is  prob- 
able that  in  vaccination  for  smallpox  the  struggle  is  less  severe 
for  the  patient,  because  the  germs  have  been  weakened  or  en- 
feebled through  residence  in  the  body  of  the  cow.  This  sug- 
gested that  disease  germs  might  be  weakened  by  heat,  cold,  di- 
lution, starvation,  etc.,  and  Pasteur  actually  produced  en- 
feebled or  ' '  attenuated ' '  cultures  of  anthrax  and  chicken  chol- 
era by  these  means. 

The  story  of  his  dramatic  public  'demonstration  of  the 
practicability  of  vaccinating  animals  against  anthrax  or  sple- 
nic fever  is  one  of  the  most  interesting  in  the  history  of 
science.  Here  he  showed  that  animals  which  had  been  vac- 
cinated with  attenuated  cultures  of  the  bacillus  were  not  sub- 
ject to  the  disease  after  inoculation  with  virulent  germs  while 
animals  which  had  not  previously  received  such  a  vaccination 
and  had  been  inoculated  with  the  same  virulent  germs  met 
death  at  the  hands  of  the  disease. 

The  experiments  began  on  May  5,  1881,  at  four  kilometers'  distance 
from  Melun,  on  a  farm  of  the  commune  of  Pouilly-le-Fort,  belonging 
to  a  veterinary  doctor  M.  Eossigiiol,  Secretary-General  of  the  Society 
of  Melun.     At  the  desire  of  the  Society  of  Agi-iculture,  a  goat  had  been 


116  HYGIENE:     DENTAL   AND    GENERAL 

substituted  for  one  of  the  twenty-five  sheep  of  the  first  lot.  On  the  5th 
of  May  they  inoculated,  by  means  of  the  little  syringe  of  Pravaz,— 
that  which  is  used  in  all  hypodermic  injections, — twenty-four  sheep, 
the  goat  and  six  cows,  with  five  drops  of  an  attenuated  splenic  virus. 

On  May  31  very  virulent  inoculation  was  effected.  Veterinary  doc- 
tors, inquisitive  people  and  agriculturists  formed  a  crowd  around  this 
little  flock.  The  thirty-one  vaccinated  subjects  awaiting  the  terrible 
trial  stood  side  by  side  with  the  twenty-five  sheep  and  the  four  cows, 
which  awaited  also  their  first  turn  of  virulent  inoculation.  Upon  the 
proposal  of  a  veterinary  doctor,  who  disguised  his  scepticism  under  the 
expressed  desire  to  render  the  trial  more  comparative,  they  inoculated 
alternately  a  vaccinated  and  a  nonvaccinated  animal.  A  meeting  was 
then  arranged  by  Pasteur  and  all  other  persons  present  for  Thursday, 
June  2,  thus  allowing  an  interval  of  forty-eight  hours,  after  the  viru- 
lent inoculation. 

More  than  tAvo  hundred  persons  met  that  day  at  Melun.  The  Prefect 
of  Seine-et-Marne,  M.  Patinot,  senators,  general  counsellors,  journal- 
ists, a  great  number  of  doctors,  of  veterinary  surgeons  and  farmers, 
tliose  who  believed  and  tliose  who  doubted  came,  impatient  for  the 
result.  On  their  arrival  at  the  farm  of  Pouilly-le-Fort,  they  could  not 
repress  a  shout  of  admiration.  Out  of  the  twenty-five  sheep  which  had 
not  been  vaccinated,  twenty-one  Avere  dead;  the  goat^  Avas  also  dead; 
two  other  sheep  were  dying,  and  the  last,  already  smitten,  was  certain 
tc  die  that  very  evening.  The  nonvaccinated  coavs  all  had  voluminous 
SAvellings  at  the  point  of  inoculation,  behind  the  shoulder.  The  fever 
was  intense,  and  they  had  no  longer,  strength  to  eat.  The  vaccinated 
sheep  were  in  full  health  and  gayety.  The  vaccinated  cows  showed  no 
tumor;  they  had  not  even  suffered  an  elevation  of  temperature,  and 
they  continued  to  eat  quietly. — -Badot/' 

Later  Pasteur  evolved  a  preventive  treatment  for  Eabies,  a 
disease  in  which  the  causative  germ  was  not  known.  In  the 
' '  Pasteur  treatment ' '  for  rabies  spinal  cords  which  are  known 
to  contain  the  germs  of  the  disease  are  removed  from  infected 
rabbits  and  the  strength  of  the  virus  is  reduced  by  extended 
periods  of  drying.  Then  as  now,  the  treatment  was  begun 
by  introducing  into  a  patient,  which  had  been  bitten  by  a 
rabid  dog,  an  emulsion  made  from  cord  which  had  been  dry- 
ing for  two  weeks.  On  the  following  days  the  emulsion  was 
made  up  from  fresher  and  fresher  spinal  cord  until  that  which 

*  Louis  Pasteur:  His  Life  and  Labors.  By  his  son-in-law.  From  the  French 
by  I^ady  Claud   Ilainiltnn.     New   York,   D.   Appleton  &  Company,   1885. 


NEW    SCIENCE    OF    DISEASE    PREVENTION  117 

had  been  dried  only  two  days  was  administered.  If  admin- 
istered first  this  Avould  have  produced  rabies  and  death.  The 
story  of  the  first  application  of  this  treatment  to  a  human  sub- 
ject in  the  successful  treatment  which  Pasteur  gave  to  the  Al- 
satian boy,  Joseph  Meister,  is  of  absorbing  interest.  (See  Life 
of  Pasteur  quoted  above.) 

In  the  cases  cited  above  the  body  became  immune  or  able 
to  combat  successfully  the  virulent  germs  by  first  conquering 
the  attenuated  or  weakened  germs  of  each  disease.  We  may 
defer  for  the  chapter  on  Immunity  the  discussion  of  the 
weapons  and  methods  of  this  struggle  because  the  activities 
of  the  germs  and  the  body  are  complex. 

Diphtheria  and  Antitoxin. — There  is  one  disease,  however, 
which  is  of  special  interest  because  a  definite  poison  (toxin) 
is  secreted  by  the  germ  just  as  the  poison  alcohol  is  secreted  as 
a  metabolic  product  of  the  yeast  cell.  In  diphtheria  a  toxin 
is  poured  out  from  the  bacterial  cells  which  is  extremely  poi- 
sonous to  certain  cells  in  the  body. 

In  1892  Berhing  and  Kitasato  discovered  that  the  blood  of 
an  animal  which  had  been  made  immune  to  the  toxin  of  diph- 
theria was  able  to  neutralize  or  impair  the  virulence  of  such 
a  toxin,  while  the  serum  of  the  nonimmune  animal  could  not. 
They  found  the  poison  produced  by  the  bacillus  of  diphtheria 
to  be  soluble  and  separated  it  from  the  germs  which  produce 
it.  We  now  secure  the  antitoxin  which  has  the  power  to  neu- 
tralize this  poison  from  the  blood  of  horses  which  have  been 
made  immune  by  injecting  small  and  increasingly  larger 
doses  of  toxin.  Since  this  antitoxin  may  be  secured  by  itself 
it  may  be  used  in  treating  the  disease  if  introduced  into  the 
body  of  the  patient,  where  it  neutralizes  the  toxins  produced 
by  the  diphtheria  bacilli. 

PREVENTIVE  SANITATION 

We  have  spoken  of  the  new  knowledge  of  germs  as  the  cause 
of  disease  and  the  development  of  the  principle  of  immunity, 
which  forms  the  basis  of  preventive  medicine.     The  second 


118  HYGIENE:     DENTAL   AND   GENERAL 

great  division  of  this  new  science  of  disease  prevention  is  pre- 
ventive sanitation. 

The  knowledge  that  diseases  were  produced  by  germs  and 
that  the  spread  of  disease  is  due  to  the  infection  of  the  healthy 
individual  with  these  living  germs  makes  it  clear  that  for  self- 
protection  society  must  prevent  the  voiding  of  germs  by  the 
diseased  person  where  they  will  be  picked  up  by  other  in- 
dividuals. The  responsibility  of  society  was  recognized  even 
before  the  development  of  the  germ  theory  of  disease  was  well 
established,  for  as  early  as  1874  there  was  a  belief  among 
experts  that  "the  existence  of  specific  poisons  capable  of  pro- 
ducing cholera  and  typhoid  fever  is  attested  by  evidence  so 
abundant  and  strong  as  to  be  practically  irresistible.  These 
poisons  are  contained  in  the  discharges  from  the  bowels  of 
persons  suffering  from  the  disease."  (Rivers  Pollution  Com- 
mission of  1868,  Sixth  Report,  London,  1874.) 

The  Epidemic  of  the  Broad  Street  Well. — One  of  the  foun- 
dation stones  for  this  belief  was  laid  in  the  excellent  work  of 
Dr.  John  Snow  of  London  in  1854,  in  investigating  an  epi- 
demic of  Asiatic  Cholera,  which  was  traced  to  the  water  of 
the  Broad  Street  well.  Inasmuch  as  this  was  the  beginning 
of  the  science  of  epidemiology  we  may  briefly  give  it  our  at- 
tention. 

During  the  epidemic  the  death  rate  in  St.  James  Parish 
was  far  higher  than  that  for  any  other  district.  Moreover 
the  deaths  were  unequally  distributed  and  had  nearly  all 
taken  place  in  the  vicinity  of  Broad  Street.  It  appeared  there- 
fore, that  there  must  be  some  other  factor  involved  than  the 
usually  accredited  causes  of  epidemics,  such  as  meteorological 
conditions,  the  general  impurity  of  the  air,  the  nature  of  the 
soil  and  the  density  of  the  population.  From  the  beginning  of 
the  outbreak  Dr.  Snow  had  taken  the  trouble  to  get  the  num- 
ber and  location  of  all  the  fatal  cases.  He  found  that  83 
deaths  took  place  during  three  days  beginning  with  August 
31.     To  quote  from  his  report: 


NEW   SCIENCE    OF    DISEASE   PREVENTION 


119 


On  proceeding  to  the  spot  I  found  that  nearly  all  the  deaths  had 
taken  place  mthin  a  short  distance  of  the  pump  in  Broad  Street.  There 
were  only  ten  (10)  deaths  in  houses  situated  directly  nearer  to  another 
street  pump.  In  five  (5)  of  these  cases  the  families  of  deceased  per- 
sons told  me  they  always  sent  to  the  pump  in  Broad  Street,  as  they 
preferred  the  water  to  that  of  the  pump  which  was  nearer.  In  three 
other   cases   the   deceased  were   children  who   went   to   school   near   the 


ASIATIC   CHOLERA 

THE  BROAD  STREET   PUMR 
LONDON  1654. 


♦  location  or  pumps. 

.  LOCATION   OF  FATAL  CHOLCRA   CASES. 

BOUnOABr  OF  E9UAL    OISTAMCES   BETWEEI 

6ROA0  STREET    PUMP  AND 
OTHER    PUMPS. 


l'"ig.    19. — Cholera    deaths   in    the    epidemic    of   the    Broad    Street    Well. 

pump  in  Ba-oad  Street.  Two  of  them  were  known  to  have  drunk  the 
water,  and  the  parents  of  the  third  think  it  probable  that  it  did  so. 
The  other  two  deaths  beyond  the  district  which  the  pump  supplies  rep- 
resent only  the  amount  of  mortality  from  cholera  that  was  occurring 
before  the  eruption  took  place. 

With  regard  to  the  73  deaths  occurring  in  the  locality  belonging,  as 
it  were,  to  the  pump,  there  were  61  instances  in  which  I  was  informed 


120  HYGIENE:     DENTAL   AND   GENERAL 

that  the  deceased  persons  used  to  diiiik  water  from  the  pump  in  Broad 
Street,  either  constantly  or  occasionally.  In  six  (6)  instances  I  could 
get  no  information,  owing  to  the  death  or  the  departure  of  every  one 
connected  with  the  deceased  individuals;  and  in  six  (6)  cases  I  was 
informed  that  the  deceased  pei'sons  did  not  drink  the  pump  water  be- 
fore their  illness. 

The  result  of  the  inquiry  consequently  was  that  there  had  been  no 
particular  outbreak  or  increase  of  cholera  in  this  part  of  London,  ex- 
cept among  the  persons  who  were  in  the  habit  of  drinking  the  water  of 
the  above-mentioned  pump  well. 

I  had  an  intendew  with  the  Board  of  Guardians  of  St.  James  Parish 
on  the  evening  of  Thursday,  7th  of  September,  and  represented  the 
above  circumstances  to  them.  In  consequence  of  what  I  said  the  handle 
of  the  pump  Avas  removed  on  the  following  day. 

Among  the  unusual  causes  which  added  confirmation  to  this 
belief  Dr.  Snow  describes  two  as  follows : 

A  gentleman  in  delicate  health  was  sent  for  from  Brighton  to  sec 
his  brother  at  No.  6  Poland  Street,  who  was  attacked  with  cholera  and 
died  in  twelve  hours,  on  the  first  of  September.  The  gentleman  ar- 
rived after  his  brother's  death  and  did  not  see  the  body.  He  only 
stayed  about  twenty  minutes  in  the  house,  where  he  took  a  hasty  and 
scanty  luncheon  of  rump  steak,  taking  with  it  a  small  tumbler  of  cold 
brandy-and-water,  the  water  being  from  the  Broad  Street  pump.  He 
went  to  P'entonville  and  was  attacked  with  cholera  on  the  evening  of 

the  following  day,  September  the  2nd,  and  died  the  next  evening.  * 
*     *     * 

The  deaths  of  Mrs.  E and  her  niece,  who  drank  the  water  from 

Broad  Street  at  the  West  End,  Hampstead,  deserve  especially  to  be  no- 
ticed. I  was  informed  by  Mrs.  E — 's  son  that  his  mother  had  not  been  in 
the  neighborhood  of  Broad  Street  for  many  months.  A  cart  went  from 
Broad  Street  to  "West  End  every  day,  and  it  was  the  custom  to  take 
out  a  large  bottle  of  the  water  fronj.  the  pump  in  Broad  Street,  as  she 
preferred  it.  The  water  was  taken  out  on  Thursday,  the  31st  of 
August,  and  she  drank  of  it  in  the  evening  and  also  on  Friday.  She 
was  seized  with  cholera  on  the  evening  of  the  latter  day,  and  died  on 
Saturday.  A  niece  who  was  on  a  visit  to  this  lady  also  drank  of  the 
water;  she  returned  to  her  residence,  a  high  and  healthy  part  of  Isling- 
ton, was  attacked  with  cholera,  and  died  also.  There  was  no  cholera 
at  this  time,  either  at  East  End  or  in  the  neighborhood  where  the 
niece  died.  Besides  these  two  persons  only  one  servant  partook  of  the 
water  at  West  End,  Hampstead,  and  she  did  not  suffer,  or,  at  least, 
not  severely.     She  had  diarrhea. 


NEW    SCIENCE    OF    DISEASE    PREVENTION  121 

The  investigation  was  further  continued  by  the  Rev.  H. 
Whitehead  who  studied  the  cause  of  the  sudden  pollution  of 
the  Broad  Street  well  which  he  believed  must  have  been  the 
cause  of  the  epidemic  referred  to  above.  He  found  that  in 
house  No.  40  Broad  Street  there  had  not  onl}'  been  four  fatal 
cases  of  cholera  at  the  time  of  the  epidemic  but  there  had 
been  earlier  cases  of  an  obscure  nature  which  were  probably 
cholera,  and  that  the  dejecta  from  these  had  been  thrown 
into  a  cesspool  very  near  the  well.  Further  investigation 
showed  that  the  bottom  of  the  main  drain  from  this  house 
lay  9  ft.  2  in.  above  the  water  level  and  that  one  drain  wsls 
so  broken  down  as  to  leak  like  a  sieve.  Moreover,  the  poorly 
constructed  cesspool  over  which  a  common  open  jDrivy  had 
been  placed  connected  with  the  drain.  The  walls  of  the  cess- 
pool were  in  the  same  leaky  condition  and  the  removal  of  the 
soil  showed  that  there  had  been  a  direct  drainage  from  both 
cesspool  and  drain  into  the  well.  The  water  had  apparently 
been  long  polluted  but  it  required  a  specific  infection  to  pro- 
duce the  outbreak  of  Asiatic  Cholera. 

Thus  water-born  disease  was  known  to  exist  before  it  was 
known  that  the  disease  was  produced  by  germs.  In  other 
words,  at  this  time  it  was  believed  that  filth  produced  certain 
diseases  because  it  produced,  harbored  and  developed  certain 
poisons  instead  of  furnishing,  as  we  now  know  to  be  the  case, 
a  temporary  abode  for  the  germs  which  have  been  thrown  off 
from  the  body  of  a  previous  case  of  the  disease. 

We  might  describe  other  epidemics  of  intestinal  disease 
which  have  been  traced  to  polluted  water  before  and  after 
the  discovery  of  the  germs  of  these  diseases.  To  this  we  could 
add  the  story  of  scores  of  epidemics  of  typhoid  fever,  scarlet 
fever,  and  diphtheria,  which  have  been  traced  to  milk  and  the 
description  of  various  other  methods  of  infection  by  means 
of  food  or  some  other  intermediate  substance. 

A  Typhoid  Fever  Epidemic  From  Oysters.^ — Perhaps  one  of 
the  most  famous  epidemiological  investigations  on  record  is 
that  made  by  Professor  H.  W.  Conn  of  Wesleyan  University 


122  HYGIENE:     DENTAL   AND   GENERAL 

in  1894.  In  this  year  there  was  an  outbreak  of  typhoid  fever 
about  October  20  which  included  over  twenty  cases  among 
the  men  of  this  coeducational  college.  No  common  bond  was 
found  among  the  victims  of  the  disease.  They  boarded  at  dif- 
ferent tables  and  many  lived  in  private  houses  in  town.  The 
wells  of  the  college  campus  were  excluded  on  the  ground  that 
they  were  used  by  town  people  as  well  as  college  students  and 
no  typhoid  fever  had  occurred  among  the  townspeople. 

Professor  Conn's  complete  and  careful  studies  developed 
along  the  lines  indicated  by  the  following  facts.  With  three 
exceptions  all  the  sick  men  belonged  to  three  fraternities. 
There  were  no  cases  among  the  women  of  the  college.  The 
water,  ice  cream,  butter  and  fruit  eaten  at  these  fraternity 
houses  were  all  excluded  as  sources  of  the  disease  because  they 
had  been  used  by  other  people  in  the  town  and  college.  The 
study  of  the  dates  showed  that  infection  took  place  about  the 
time  of  a  series  of  fraternity  suppers.  One  of  the  cases  not 
belonging  to  a  fraternity  had  attended  such  a  supper.  The 
menu  of  these  suppers  were  studied  and  all  foods  excluded 
except  raw  oysters.  It  was  then  found  that  the  women  of 
the  college  did  not  hold  any  special  supper  on  this  date  and 
did  not  eat  raw  oysters.  Of  the  other  four  fraternities,  among 
which  there  were  no  cases,  two  did  not  use  oysters  at  initiation 
suppers,  one  obtained  them  from  Hartford  instead  of  Middle- 
town  dealers  and  the  fourth  used  oysters  but  in  the  cooked  and 
not  the  raw  state.  None  of  the  families  in  town  which  bought 
oysters  from  this  lot  had  eaten  them  raw.  An  attendant  who 
had  eaten  oysters  from  this  batch  in  the  home  of  the  dealer 
had  had  a  mild  run  of  the  fever.  Many  alumni  and  five  Yale 
students  were  present  at  the  banquet.  Among  these  there 
were  several  cases  of  slight  illness,  diarrhea,  weakness,  and 
four  cases  of  genuine  typhoid  fever.  Two  of  the  five  Yale 
students  developed  the  disease. 

The  study  of  the  source  of  the  oysters  showed  that  they 
had  been  taken  from  deep  water  in  Long  Island  Sound,  had 
been  brought  to  the  mouth  of  a  creek  near  Fair  Haven, 


NEW   SCIENCE    QF   DISEASE   PREVENTION  123 

Connecticut  for  fattening.  Three  hundred  feet  from  the  beds 
M'here  the  oysters  were  fattened  there  existed  the  outlet  from 
the  sewer  of  a  private  house  in  which  there  were  two  cases  of 
typhoid  fever.  The  current  of  water  at  this  point  showed 
that  the  effluent  from  this  sewer  would  almost  certainly  be 
distributed  over  the  beds  in  which  the  oysters  were  fattened. 

These  examples  of  the  early  and  startling  discoveries  of  the 
transmission  of  disease  from  the  sick  to  the  well  by  means  of 
some  intermediate  substance  show  the  basic  principle  upon 
which  the  science  of  preventive  sanitation  has  been  developed. 

The  knowledge  of  germs  as  the  cause  of  disease,  their  via- 
bility in  water,  milk,  and  other  foods,  and  the  methods  by 
which  they  may  be  destroyed  has  made  it  possible  to  develop 
scientific  means  of  sewage  disposal,  water  purification,  and  the 
protection  of  food  materials.  The  practical  details  of  applied 
sanitation  in  these  various  fields  will  be  later  considered. 


PREVENTIVE  HYGIENE 

Preventive  hygiene  or  the  conduct  of  individuals  in  such 
a  way  as  to  avoid  infection  and  communicable  disease  is  based 
upon  our  knowledge  of  both  preventive  medicine  and  pre- 
ventive sanitation.  Our  habits  are  now  influenced  by  our 
knowledge  of  the  germs  of  particular  diseases,  their  mode  of 
life  and  the  manner  in  which  they  may  be  transferred;  so 
that  in  our  daily  activities  we  avoid  opportunities  for  infec- 
tion. Promiscuous  kissing,  the  use  of  common  drinking  cups, 
and  the  eating  of  food  prepared  and  served  by  people  of  un- 
cleanly habits  whose  freedom  from  infectious  disease  can  not 
be  vouched  for;  these  and  many  other  unhygienic  habits  are 
automatically  condemned  by  our  knowledge  of  germ  diseases. 
These  dangers  of  infection  will  be  considered  further  in  our 
discussion  of  special  diseases. 

Resistance. — Preventive  hygiene  must  consider  still  another 
feature  in  resisting  infection  and  particularly  in  successfully 
withstanding   an   infectious   disease.     Pasteur    demonstrated 


124  HYGIENE:     DENTAL    AND   GENERAL 

that  the  outcome  of  the  battle  between  man  and  the  microbe 
may  be  determined  by  weakening  or  attenuating  the  latter  or 
by  building  up  a  specific  resistance  of  the  human  body. 
Dr.  Theobold  Smith  has  spoken  of  disease  in  terms  of  the 

formula  D  =  ;  when  D  =    the  disease ;  N  =  the  num- 

R 

ber  of  organisms  in  the  initial  infection ;  V  =  the  virulence 
of  the  germs ;  and  R  =  the  resistance  of  the  individual. 
This  resistance  in  many  cases  is  specific  for  the  disease 
in  question  but  for  other  diseases,  like  Tuberculosis,  the  re- 
sistance may  be  related  to  the  bodily  vigor  and  general  health 
of  the  individual.  So  that  personal  hygiene,  which  assists  in 
building  up  a  strong  and  healthy  body,  is  related  to  disease 
prevention  and  is  important  in  disease  as  well  as  in  health. 

Summary. — We  have  seen  the  origin  of  three  united  sciences 
by  referring  to  the  history  of  disease  prevention  and  the  dis- 
covery of  germs  as  the  cause  of  disease. 

Preventive  medicine  reaches  back  to  the  experiments  of 
Pasteur  in  producing  immunity  to  a  specific  disease  and  in- 
volves all  the  more  recent  developments  of  this  art  by  the  use 
of  specific  vaccines,  antitoxins,  viruses  and  drugs  to  assist  the 
person  to  throw  off  or  withstand  infectious  diseases.  Prevent- 
ive sanitation  rests  upon  this  new  knowledge  of  disease  causa- 
tion and  by  its  application  prevents  the  spread  of  infection 
from  the  sick  to  the  healthy  either  directly  or  indirectly 
through  the  application  of  quarantine,  the  supervision  of 
water,  milk,  and  other  food  supplies,  the  purification  of  sew- 
age, and  the  prevention  of  other  conditions  which  would  make 
it  possible  for  live  germs  to  reach  and  infect  healthy  individ- 
uals. Preventive  hygiene  recognizes  the  infectious  agents  of 
disease  and  prescribes  for  individuals  a  course  of  conduct 
which  is  best  calculated  to  avoid  infection. 


CHAPTER  VII 

ESSENTIAL  FACTS  OF  IMMUNITY 

The  presence  of  an  immunity  is  easier  to  understand  than 
the.  process  by  which  it  is  secured.  For  the  ordinary  in- 
dividual the  fact  is  all  important  but  the  science  of  immu- 
nology is  the  foundation  of  the  art  of  preventive  medicine  and 
a  brief  statement  of  the  essential  facts  in  this  rapidly  develop- 
ing science  has  a  place  in  any  extended  discussion  of  the  sub- 
ject of  hygiene. 

Immunity  Defined. — Immunity  is  a  common  property  of 
life  which  may  be  defined  as  the  power  of  the  organism  to  re- 
sist infection.  It  is  opposite  in  meaning  to  the  word  suscep- 
tibility and  both  these  words  are  relative  terms.  Immunity 
may  be  complete,  or  so  weak  as  to  be  hardly  appreciable.  In 
many  instances  we  use  the  term  resistance  as  equivalent  to 
immunity. 

Another  variable  quantity,  which  is  always  related  to  the 
immunity  of  the  patient,  is  the  virulence  of  the  disease-pro- 
ducing organism.  By  virulent  we  mean  poisonous  or  deadly 
and  we  find  that  different  strains  of  germs  have  varying  abil- 
ities in  their  power  of  evil  just  as  individuals  have  the 
varying  powers  of  resistance. 

We  may  illustrate  immunity  with  an  analogy  from  inter- 
national experience.  It  is  not  now  difficult  for  us  to  con- 
ceive of  a  nation  thirsting  for  world  power  and  opposed  to 
the  welfare  of  the  great  body  of  humanity  outside  that  nation. 
The  people  of  such  a  country  may  represent  the  germs  of  a 
disease  and  the  great  body  of  humanity,  the  person  subject  to 
the  disease.  The  individuals  of  such  a  nation  usually  appear 
innocent  enough  and,  like  the  germs  of  disease,  quite  similar 
to  their  harmless  neighbors.     There  finally  arises  an  oppor- 

125 


126  HYGIENE:     DENTAL  AND   GENERAL 

tunity  for  the  invasion  of  other  lands  and  these  people  make 
war  upon  the  rest  of  the  world  just  as  the  germs  enter  into 
a  struggle  with  the  human  body.  If  they  are  successful  the 
life  of  the  invaded  nations  comes  to  an  end;  if  they  are  not 
successful  in  their  war  they  are  eliminated  from  the  territory 
which  they  have  overrun  and  their  armies  are  reduced  in 
strength  and  vitality,  for  the  time  being,  just  as  the  virulence 
of  influenza  seems  to  be  reduced  after  the  first  severe  epidemic. 
But  the  other  peoples  of  the  world,  if  they  are  wise  enough 
to  realize  the  danger  from  this  lust  for  world  conquest,  will 
set  up  barriers  against  the  return  of  a  world  war  and  if 
these  barriers  are  strong  enough  future  recurrences  may  be 
avoided.  These  barriers,  like  the  factors  of  immunity,  are 
varied,  numerous  and  complex.  They  may  consist  of  a  new 
army  to  combat  the  destructive  forces  of  the  enemy,  of  mili- 
tary barriers  set  up  against  the  entrance  of  the  foe  or  a  gen- 
eral readiness  of  the  peoples  to  respond  immediately  to  a 
threat  of  a  new  attack.  Likewise  the  human  body  when  at- 
tacked by  the  germs  of  disease  may  create  new  defensive  sub- 
stances which  remain  in  the  blood,  the  tissues  subject  to  mi- 
crobial invasion  may  become  more  resistant  to  the  particular 
organism  or  the  whole  bodily  reaction  may  be  more  prompt 
and  effective  at  a  second  attack. 

Our  knowledge  of  immunity  has  been  gained  from  the  ob- 
servation of  diseases  and  from  experimental  biology  but  not 
from  chemistry.  In  other  words,  we  are  not  yet  able  to  state 
the  chemical  reactions  in  immunity  and  disease  and  we  must 
expand  the  science  by  a  study  of  the  reactions  of  experimental 
animals  and  the  reactions  of  the  immune  substances  which 
they  produce. 

We  should  recognize  at  the  outset  that  the  resistance  of  an 
individual  to  disease  is  determined  by  two  factors,  his  general 
bodily  health  or  vigor  and  the  presence  or  absence  of  specific 
immune  substances  in  the  blood.  These  two  factors  are  not 
of  the  same  relative  importance  in  all  diseases.  In  cases  of 
tuberculosis,  pneumonia  and  colds  or  in  cases  of  sepsis,  bodily 


ESSENTIAL   FACTS   OF   IMMUNITY  127 

vigor  is  very  important.  In  most  of  the  contagious  diseases 
such  as  scarlet  fever,  small  pox,  typhoid  fever,  and  measles, 
however,  general  good  health  is  of  little  importance  in  with- 
standing the  infection  and  immunity  can  only  be  secured 
through  the  presence  of  immune  substances  in  the  body.  It 
may  be  that  the  importance  of  bodily  vigor  in  combating  tu- 
berculosis, colds  and  other  respiratory  diseases,  is  related  to 
the  important  part  played  by  the  living  cells  (phagocytes). 
Although  the  diseases  in  this  group  are  not  numerous  they  are 
very  important  and  we  may  do  well  to  begin  by  enumerating 
some  of  the  most  important  factors  in  destroying  immunity 
through  the  reduction  of  bodily  vigor. 


NONSPECIFIC  IMMUNITY 

The  things  which  most  frequently  break  down  the  non- 
specific immunity  or  general  vitality  are  the  following: 

1.  Fatigfue. — Experimentally  it  has  been  found  that  white 
rats  are  more  susceptible  to  anthrax  after  being  worked  in  a 
revolving  cage ;  and  it  has  also  been  found  that  the  defensive 
powers  of  dogs,  rabbits  and  guinea  pigs  against  typhoid  are 
reduced  by  excessive  exercise.  It  is  hard  to  explain  how 
fatigue  produces  these  results  unless  we  accept  the  suggestion 
that  katabolic  products  of  muscular  activity  are  injurious  to 
the  cells,  especially  the  white  blood  cells  which,  as  we  shall  see 
later,  play  an  important  part  in  immunity.  It  is  known  that 
these  products  are  acid  and  that  some  of  the  protective  sub- 
stances in  the  body  (alexins  and  opsonins)  act  best  in  an  al- 
kaline medium. 

2.  Exposure  to  Wet  and  Cold. — Exposure  to  wet  and  cold 
reduces  the  power  of  resistance  to  disease,  as  has  been  demon- 
strated in  the  case  of  fowls  which  are  naturally  immune  to 
anthrax  but  contract  the  disease  after  standing  some  time  in 
cold  water.  We  know  that  such  exposure  cools  the  blood  and 
must  therefore  reduce  the  activity  of  the  leukocytes.  It  may 
also  reduce  the  production  of  defensive  substances  in  the 


128  HYGIENE:     DENTAL    AND    GENERAL 

body.  This  relation  to  temperature  would  explain  how  mus- 
cular exercise  reduces  the  danger  of  diseases  under  exposure 
to  cold  and  wet  hy  keeping  up  the  body  temperature.  Sud- 
den exposure  to  dampness  and  cold,  especially  if  the  individ- 
ual had  reduced  the  efficiency  of  the  heat-regulatiug  system 
of  the  body  through  improper  clothing  and  poor  ventilation, 
would  produce  a  lowered  resistance  in  this  manner. 

3.  Drugs. — Excesses  in  the  use  of  drugs  and  alcohol  are 
well  known  and  important  in  increasing  the  susceptibility  to 
tuberculosis.  The  factors  involved  here  may  be  the  lowering 
of  the  temperature,  the  destruction  of  delicate  defensive  sub- 
stances in  the  body  and  the  inhibition  of  leukocyte  activity. 

5.  Undereating-. — Insufficient  and  unsuitable  food  accel- 
erates tuberculosis.  This  may  be  explained  by  the  fact  that 
digestion  increases  leukocytosis.  Moreover,  infection  is  more 
likely  to  pass  through  an  empty  stomach  than  one  where 
acid  digestion  is  rapidly  taking  place. 

5.  Oral  Defects. — Bacteria  which  are  groAAing  in  decaying 
teeth  or  in  chronically  inflamed  tonsils'  are  producing  poisons 
which  continually  tax  the  protective  powers  of  the  body  and 
therefore  make  it  easier  for  other  infective  organisms  to  enter 
and  produce  disease.  Moreover  a  dirty  mouth,  already  har- 
boring a  variety  of  bacteria,  is  a  better  culture  place  for 
disease  germs  than  is  a  clean  mouth.  Enlarged  tonsils  and 
adenoids  reduce  the  body  vigor  by  their  injurious  effect  upon 
breathing  and  nutrition. 

SPECIFIC  IMMUNITY 

Specific  immunity  exists  by  virtue  of  certain  substances 
(immune  bodies  or  antibodies)  present  in  the  blood,  which 
prevent  or  retard  the  development  of  the  disease  in  question. 
It  may  be  natural  or  acquired,  general  or  local.  Acquired 
immunity  may  be  active  or  passive. 

Natural  Immunity. — Certain  species  of  animals  are  immune 
to  the  diseases  which  affect  other  species.     For  example,  the 


ESSENTIAL    FACTS    OF    IMMTXITY  129 

lower  animals  are  immune  to  many  of  the  communicable 
diseases  of  man  such  as  cholera,  typhoid  fever,  mumps,  measles, 
scarlet  fever,  yellow  fever,  malaria,  leprosy,  etc.  Man  is  im- 
mune to  many  of  the  diseases  which  attack  lower  animals. 
There  are  certain  germs,  however,  which  attack  many  species 
of  widely  different  genera.  Examples  of  this  group  include 
the  organisms  of  tetanus,  malignant  edema,  anthrax,  pus  for- 
mation, glanders,  plague,  rabies,  Malta  fever,  foot-and-mouth 
disease,  milk  sickness,  ringworm,  and  paratyphoid  fever. 

Local  Immunity. — Many  tissues  of  the  body  appear  to  be 
immune  to  diseases  which  do  serious  damage  to  other  tissues. 
For  example,  diphtheria  does  not  often  extend  from  the  throat 
down  the  esophagus.  There  may  even  be  a  difference  in 
the  susceptibility  of  the  same  tissue  at  different  periods  of 
life.  In  general,  tissues  which  are  well  flushed  with  blood  are 
relatively  immune.  Prompt  local  reaction  frequently  saves 
the  more  remote  tissues  of  the  body  by  holding  back  the  organ- 
isms and  in  general  this  is  a  good  indication  of  immunity. 

Acquired  Immunity. — Acquired  immunity  is  specific  for 
particular  diseases  and  is  not  inherited.  It  may  be  secured 
by  having  the  disease  or  artificially  induced  by  the  injection 
of  a  virus  or  a  vaccine.  B.y  virus  we  mean  the  living  organism 
of  infection  and  by  a  Ixicferial  vaccine  the  killed  organism 
of  the  infection.  It  is  obvious  that  the  virus  must  be  reduced 
in  virulence  or  introduced  in  very  small  quantities  while  the 
vaccine  is  less  severe  and  more  likely  to  produce  a  local  re- 
action followed  b.y  a  brief  general  reaction.  Sometimes  sen- 
sitized vacccines  are  produced  by  mixing  the  bacteria  with  the 
specific  antibodies  from  the  blood  serum  of  an  animal  which 
has  been  rendered  immune.  Polyvalent  vaccines  are  made  up 
from  several  strains  of  the  same  organism.  Mixed  vaccines 
containing  the  dead  bacilli  of  two  or  more  diseases  like  ty- 
phoid, paratyphoid  and  cholera  are  sometimes  used.  Immun- 
ity acquired  through  tlie  use  of  vaccines  usually  lasts  from 
two  to  five  vears. 


130  HYGIENE:     DENTAL    AND    GENERAL 

Active  and  Passive  Immunity. — The  above  description  re- 
fers to  active  immunity.  In  other  cases  the  immunity  may  be 
passive  or  mixed.  In  diphtheria  the  horse  from  which  anti- 
toxin is  secured  is  rendered  immune  to  the  disease  by  the  in- 
jection of  increasing-  doses  of  diphtheria  toxin  and  his  immun- 
ity is  active.  The  patient  may  be  made  temporarily  immune 
by  the  injection  of  immune  substances  from  tlie  blood  serum 
of  the  horse.  This  immunity  is  passive  or  transferred  and  is 
of  brief  duration.  Mixed  immunity  is  produced  by  injecting 
immune  substances  from  another  animal  with  the  vaccine  or 
toxin  as  exemplified  in  the  use  of  plague  vaccine  with  plague 
antitoxin  or  in  the  use  of  a  toxin-antitoxin  mixture  to  im- 
munize against  diphtheria. 

Carriers. — Usually  after  a  disease  the  body  rids  itself  en- 
tirely of  the  germs.  Occasionally,  however,  this  does  nor 
happen  and  a  condition  of  mutual  tolerance  is  set  up.  This 
'' immunity  without  disinfection"  is  a  condition  in  which  the 
patient  continues  to  be  a  carrier  of  the  germs.  The  reaction 
between  the  patient  and  the  infective  organism  is  not  serious. 
They  have  acquired  the  ability  of  tolerating  each  other,  and 
the  reaction  by  each  has  apparently  become  milder.  Carriers 
are  found  in  diphtheria,  typhoid,  cholera,  epidemic  cerebro- 
spinal menengitis,  influenza  and  in  certain  protozoan  diseases 
like  malaria.  Many  epidemics  have  been  traced  to  such  car- 
riers. There  is  always  a  possibility  of  a  spread  of  the  disease 
in  this  fashion  and  in  some  instances  the  lowered  vitality  of 
the  individual  may  result  in  a  relapse  of  his  own  case. 

Disease  Reactions, — Just  as  different  agricultural  plants 
grow  best  in  different  soils,  select  somewhat  different  foods, 
and  produce  different  products,  so  the  germs  of  disease  vary 
in  the  part  of  the  body  which  they  attack  and  differ  in  their 
life  processes  and  in  the  effects  they  produce  upon  the  indi- 
vidual. The  actions  and  reactions  between  the  various  mi- 
crobes and  man  are  numerous  and  complex.  This  is  not  the 
place  for  an  extended  discussion  of  them ;  but  they  have  such 
an  important  bearing  upon  our  comprehension  of  disease  and 


ESSENTIAL    FACTS    OF    IMMITNITY  131 

the  terms  are  so  rapidly  finding  a  place  in  our  everyday  vo- 
cabulary that  a  brief  description  of  the  terminology  and  phe- 
nomena may  be  found  useful  to  the  dental  student  and  prac- 
titioner. We  shall  therefore  consider  briefly  the  nature  of 
the  struggle  waged  during  the  course  of  an  infectious  disease. 

Toxins. — There  are  two  types  of  bacterial  poisons  Avhich 
produce  disease,  exotoxins  and  endotoxins.  The  true  toxin 
(exotoxin)  is  defined  by  Rosenau  as  "a  specific  poison  elab- 
orated by  bacterial  metabolism ;  it  is  soluble  in  water ;  poison- 
ous in  minute  amounts;  reproduces  the  essential  symptoms 
and  lesions  of  the  disease;  acts  only  after  a  period  of  incu- 
bation; and  produces  antibodies,  namely,  antitoxin."  Such 
toxins  are  complex  chemical  substances  probably  belonging 
to  the  liigher  proteins.  They  are  thermolabile  and  unstable. 
Three  such  substances  are  well  known,  the  toxins  produced  in 
diphtheria,  tetanus,  and  botulism.  Other  bacteria,  such  as 
dysentery,  pyocyaneus  and  cholera  produce  soluble  toxic  sub- 
stances which  do  not,  however,  have  all  the  above  named  char- 
acteristics. 

We  should  add  that  many  bacteria  produce  poisonous  sub- 
stances of  another  type  such  as  ferments,  iDtomains,  acids, 
alkalis,  nitrites  and  hydrogen  sulphid.  The  bacilli  of  tuber- 
culosis and  glanders  form  soluble  toxic  substances  which  are 
specific  but  (in  small  quantities)  harmless  in  a  normal  animal, 
being  poisonous  only  to  an  animal  suffering  with  the  specific 
disease. 

There  are  also  toxins  from  the  higher  plants  such  as  riciu 
from  the  castor  bean  and  abrin  from  the  jequirity  bean.  These 
so-called  phytotoxins  comply  with  the  above  definition  of  a 
true  toxin  in  most  respects.  The  venoms  produced  by  wasps, 
scorpions,  spiders,  and  snakes  are  very  similar  substances. 

In  the  case  of  the  true  toxin  it  is  impossible  to  say  whether 
it  is  a  secretion  or  an  excretion  or  the  result  of  the  action  of 
the  bacteria  upon  the  medium.  There  are  four  important 
characteristics  of  these  toxins.  They  are  destroyed  by  boiling 
or  by  heating  at  G3  degrees  C.  for  a  short  time.     They  are 


132  HYGIENE:     DENTAL   AND    GENERAL 

extremely  poisonous  in  small  quantities  (0.000,000,05  of  a 
gram  of  tetanus  toxin  is  sufficient  to  kill  a  mouse).  They 
produce  their  effect  after  an  incubation  period  and  have  a 
specific  combining  affinity  for  particular  cells  of  the  body. 

Endotoxins. — Certain  bacteria  contain  internal  poisons 
which  may  be  liberated  when  the  bacterial  cells  die.  It  is 
possible  to  obtain  endotoxins  by  grinding  the  cells  of  the 
dysentery  bacillus  and  the  cholera  vibrio.  We  should  not 
conclude,  however,  that  endotoxins  are  similar  in  their  action 
and  composition  to  true  or  exotoxhm.  It  may  be  moreover 
that  the  split  protein  products  of  the  bacteria  themselves  act 
as  poisons  to  the  body  cells. 

Reactive  Phenomena. — The  body  has  been  found  to  react  in 
definite  ways  to  particular  diseases  and  our  knowledge  of  the 
basis  of  immunity  rests  upon  the  study  of  these  phenomena 
M^hich  include  (1)  phagocytosis,  (2)  anaphylaxis,  and  (3) 
the  production  of  specific  substances  like  antitoxins,  opsonins, 
lysins,  precipitins,  and  agglutinins. 

1.  Phagocytosis.  The  important  work  of  Metchnikoff  in 
the  study  of  immunity  showed  that  certain  bacteria  are  de- 
voured and  digested  in  great  numbers  by  the  cells  of  the  body. 
Cells  which  accomplish  this  task  are  of  two  types :  the  motile 
cells  (white  blood  cells)  and  the  fixed  cells  of  the  connective 
tissue  and  endotlielium.  Metchnikoff  believed  this  phenome- 
non of  phagocytosis  to  be  the  principal  bodily  activity  in 
combating  disease  and  producing  immunity. 

These  cells  are  susceptible  to  chemotactic  infiuences  and  it 
is  conceivable  that  the  attack  of  a  disease  might  so  accelerate 
their  activity  that  at  the  inception  of  a  second  infection  the 
invading  bacteria  might  be  devoured  before  the  disease  could 
be  produced.  Phagocytosis  however  is  not  a  complete  and 
adequate  explanation  for  immunity  unless  it  is  believed  that 
the  phagocytic  cells  produce  special  immune  bodies — to  be 
considered  later. 

Opsonins. — Phagocytosis  has  beeen  found  to  take  place  only 
in  the  presence  of  certain  substances  which  prepare  the  bac- 


ESSENTIAL   FACTS   OF    IMMUNITY  133 

teria  for  phagocytic  digestion.  These  substances,  which  are 
called  opsonins,  are  normally  present  but  may  be  increased 
by  the  injection  of  bacteria  or  a  specific  antigen.  They  com- 
bine with  the  bacteria  and  phagocytosis  does  not  take  place 
without  them.  The  opsonic  index  which  is  used  in  vaccine 
therapy  is  the  measure  of  these  substances  as  determined  by 
the  "avidity"  with  which  phagocytic  cells  dcA^our  the  bac- 
teria. 

2.  Anaphylaxis. — Anaphylaxis  or  hypersusceptibility  is  a 
condition  of  the  body  in  which  it  is  unusually  susceptible  to 
foreign  proteins.  This  is  a  specific  reaction  which  may  be 
developed  against  certain  bacteria  or  other  protein  substances. 
It  may  be  congenital  or  acquired,  local  or  general 

An  example  of  anaphylaxis  as  produced  by  an  ordinarily 
harmless  substance  is  secured  by  the  injection  of  horse  serum 
into  a  guinea  pig.  If  the  second  injection  of  serum  is  sepa- 
rated from  the  first  by  an  interval  of  eight  to  fourteen  days 
it  produces  what  is  known  as  acute  anaphylactic  shock.  The 
guinea  pig  becomes  restless,  manifests  difficulty  in  breathing, 
is  generally  agitated  and  discharges  both  urine  and  feces. 
There  may  soon  follow  complete  paralysis,  the  arrest  of 
breathing,  and  death.  The  guinea  pig  is  apparently  much 
more  susceptible  to  this  reaction  than  any  other  animal.  The 
explanation  of  this  fact  and  the  phenomenon  itself  is  fur- 
nished by  Schultz  who  showed  that  serum  anaphylaxis  pro- 
duces the  hypersensitization  of  smooth  muscle  tissue  which 
contracts  during  shock  Math  the  fatal  results,  in  the  case  of  the 
guinea  pig,  because  the  mucosal  layer  of  its  secondary  bronchi 
is  thrown  into  folds  by  the  contraction  of  this  muscle  and 
breathing  is  inhibited.     This  reaction  is  strictly  specific. 

By  examples  of  other  types  of  anaphyhixis  it  may  be  seen 
how  this  increased  sensitivity  of  the  tissue  to  particular  germs 
may  produce  a  very  prompt  reaction  which  may  be  connected 
with  acquired  immunity.  In  the  second  vaccination  for  small- 
pox the  incubation  period  is  much  shorter  and  in  the  prompt 
"take"  the  reaction  is  less  severe.     It  appears  in  this  case 


134  HYGIENE :     DENTAL   AND    GENERAL 

that  immunity  is  not  complete  but  the  protection  is  dependent 
upon  anaphylaxis.  In  other  diseases  this  prompt  reaction 
may  prevent  the  development  of  the  clinical  symptoms. 

In  guinea  pigs  such  a  sensitization  may  be  produced  by 
feeding  them  meat  or  serum  and  the  mother  guinea  pig  may 
transmit  a  hypersensibility  to  the  toxic  action  of  horse  se- 
rum to  her  3^oung.  We  may  raise  the  question  as  to  whether 
these  facts  may  not  explain  why  symptoms  like  those  in  ana- 
phylactic shock  sometimes  follow  the  eating  of  fish  and  other 
articles  of  diet  and  whether  this  phenomenon  explains  a  pos- 
sible inherited  susceptibility  to  tuberculosis. 

The  serum  sickness,  which  often  takes  place  from  12  to  14 
days  after  the  injection  of  antitoxic  sera  and  show^s  symptoms 
of  fever,  itching  and  pain  at  the  point  of  injection  and  a 
general  urticaria,  may  be  the  anaphylactic  reaction  from  these 
substances  still  remaining  in  the  body  at  the  end  of  the  incu- 
bation period.  The  substances  which  produce  serum  sickness 
however  are  the  proteins  of  the  horse  serum  and  not  the  anti- 
toxin itself. 

In  considering  other  examples  of  anaphylaxis  it  is  to  be 
noted  that  in  most  febrile  diseases  there  is  a  ten  to  fourteen 
day  incubation  period  before  the  general  bodily  reaction 
marks  the  beginning  of  the  active  period  of  disease.  Diphthe- 
ria or  other  diseases  where  soluble  toxins  are  produced  obvi- 
ously do  not  belong  in  this  class.  Tuberculin  (a  glycerine 
extract  from  tubercule  bacilli)  is  not  poisonous  to  a  healthy 
individual  but  produces  a  definite  reaction  in  a  tuberculous 
individual  because  he  has  become  anaphylactic  to  the  disease. 
This  test  for  hypersusceptilnlity,  therefore,  may  be  used  in 
detecting  the  disease.  It  may  also  be  seen  that  the  hypersus- 
ceptibility  of  the  tissue  produces  a  prompt  reaction  Avhich 
helps  to  encapsulate  the  organisms. 

It  lui.s  long  been  known  that  in  many  people  fish,  tomatoes 
and  cheese  are  likely  to  i:)roduce  an  urticarial  rash ;  eggs  may 
produce  asthmatic  syraptoins;  and  cereals,  pork  and  milk  may 
produce  ei-ythenias.     Tliese  cases  and  many  cases  of  eczema 


ESSENTIAL    FACTS    OF    IMMUNITY  135 

may  be  due  to  anaphylactic  reactions  to  the  special  i)roteins. 

Anaphylaxis  in  hay  fever  is  the  hypersusceptibility  of  the 
mucous  membrane  of  the  respiratory  tract  to  the  pollen  of 
ragweed,  golden  rod  and  other  plants.  Dust  emanations  from 
horses  or  other  animals  or  hyperacidity  of  the  gastric  juice 
may  produce  similar  conditions.  Puerperal  eclampsia,  the 
onset  of  labor,  and  the  crisis  in  pneumonia  have  been  in  part 
explained  by  the  phenomena  of  anaphylaxis. 

3.  Specific  Substances. — Antitoxins. — Antitoxins  are  sub- 
stances formed  in  an  animal  by  the  stimulation  of  specific 
toxins.  They  are  capable  of  neutralizing  the  corresponding 
toxins.  They  are  substances  of  complex  chemical  composi- 
tion, more  stable  than  toxins  although  destroyed  by  heat,  acids 
and  many  other  chemicals.  These  substances  appear  in  the 
blood  and  in  all  the  fluids  and  excretions  of  the  immune  ani- 
mals. When  they  are  introduced  into  the  body,  as  in  the  use 
of  diphtheria  antitoxin  from  the  horse,  they  disappear  rather 
(juickly,  uniting  with  the  toxin  or  with  the  body  cells  but 
mainly  finding  exit  through  the  urine,  bile  and  saliva  in  the 
form  of  antitoxin.  Passive  immunity  therefore  is  transient 
and  lasts  usually  from  ten  to  fourteen  days  wdiile  active  im- 
munity is  of  much  longer  duration.  Antitoxins  are  not  always 
produced  as  a  reaction  to  bacterial  toxins  even  in  susceptible 
animals.  A  guinea  pig  which  is  highly  susceptible  to  diph- 
theria will  not  produce  any  antitoxin. 

It  can  be  shown  that  there  is  a  direct  union  between  anti- 
toxin and  toxin  by  mixing  the  two  in  a  test  tube  and  then 
injecting  the  mixture  into  a  susceptible  animal.  This  injec- 
tion pr(;duces  no  observable  or  injurious  result.  After  the 
toxin  has  once  been  united  with  the  body  cells  liowever  it 
cannot  be  dislodged  by  an  antitoxin.  It  may  thus  be  seen  wli>' 
moderate  amounts  of  diphtheria  antitoxin  in  the  earlier  stages 
of  the  disease  are  more  efficacious  than  large  doses  adminis- 
tered at  a  later  period.  Antitoxin  may  l)e  present  in  the  l)lood 
liefore  infection  takes  place. 


136  HYGIENE  :     DENTAL    AND    GENERAL 

Agglutinins. — Widal  showed  that  very  dilute  mixtures  of 
the  blood  serum  of  a  typhoid  patient  will  cause  the  typhoid 
bacilli  to  agglutinate,  that  is,  to  lose  their  motility  and  gather 
in  little  clumps.  These  small  groups  may  be  seen  under  the 
microscope  or  as  flakes  in  a  test  tube  suspension.  It  was  later 
found  that  agglutinating  substances  may  be  produced  in  the 
blood  by  injecting  dead  bacteria  into  the  body,  as  in  typhoid 
vaccination. 

Agglutination  does  not  harm  the  bacteria  by  rendering  them 
motionless.  They  may  again  multiply  and  grow  vigorously. 
The  so-called  germicidal  property  of  freshly  drawn  milk  is 
probably  mainly  a  phenomenon  of  agglutination,  since  the 
bacteria  are  clumped  together  and  only  one  colony  for  each 
clump  of  organisms  is  developed  on  the  agar  plate. 

Agglutinins  are  not  absolutely  specific  since,  if  they  are 
used  in  large  quantities,  closely  allied  species  of  bacteria  may 
also  be  agglutinated.  They  are  however,  quantitatively  spe- 
cific, since  the  corresponding  organisms  will  be  agglutinated 
by  a  greater  dilution.  Agglutination  may  also  be  produced 
for  red  blood  corpuscles  and  protozoa.  The  part  which  these 
substances  play  in  immunity  is  not  yet  clear. 

Precipitins. — In  1897  Kraus  showed  that  it  is  possible  to 
produce  another  type  of  immune  body  in  the  blood  serum  of 
an  animal  by  the  injection  of  bacteria  or  albuminous  sub- 
stances. When  the  clear  serum  of  an  immunized  animal  was 
added  to  the  clear  antigen  the  resulting  fluid  became  opaque 
from  the  formation  of  a  precipitate  which  soon  settled  to  the 
bottom  of  the  test  tube.  This  discovery  was  made  by  adding 
some  typhoid  serum  to  a  filtered  culture  of  typhoid  bacilli. 
Certain  other  organisms  like  cholera  and  plague  produce  the 
same  phenomenon  but  not  all  bacteria  do  this  and  the  diph- 
theria bacillus  is  the  important  example  of  the  latter  class. 
This  precipitation  is  similar  to  the  agglutination  of  bacteria 
and  is  a  reaction  of  protein  molecules  which,  as  we  know,  are 
not  true  solutions  but  colloidal  suspensions.  The  relation  of 
these  substances  to  immunity  is  not  clear  but  we  may  see  how 


ESSENTIAL   FxVCTS    OP   IMMUNITY  137 

it  maj'  be  possible  for  them  to  throw  down  poisons  from  solu- 
tion and  make  them  inert. 

Lysins. — In  1896  Dr.  Pfeiffer  observed  that  when  living 
cholera  vibrio  were  injected  into  a  peritoneal  cavity  of  guinea 
pigs  wJiich  had  been  previously  immunized  against  cholera  the 
germs  lost  their  power  of  motion,  became  grouped  together  in 
clumps  and  were  finally  completely  dissolved.  This  reaction 
which  is  specific  for  special  diseases  is  known  as  Pfeiffer's 
phenomenon,  and  the  substances  which  have  the  power  of 
disintegrating  or  dissolving  cells  or  other  organized  substances 
introduced  into  the  body  are  called  lysins.  Those  which  dis- 
integrate bacteria  are  called  bacteriolysins,  those  which  dis- 
solve the  red  blood  corpuscles  of  other  animals  are  called 
hemolysins,  and  those  which  dissolve  the  cells  of  glandular 
tissues  are  called  cytolysins.  The  normal  bacteriolytic  proper- 
ties of  the  blood  are  thought  to  be  due  almost  entirely  to  a 
similar  nonspecific  substance  which  dissolves  the  various  bac- 
terial cells.  It  is  this  power  which  enables  the  blood  to  resist 
decomposition  longer  than  other  animal  fluids. 

That  the  complete  explanation  of  immunity  is  not  furnished 
by  the  lysins  is  shown  by  the  fact  that  animals  may  be  sus- 
ceptible to  disease  although  the  blood  possesses  bactericidal 
properties.  In  anthrax  the  rabbit  is  very  susceptible  although 
the  blood  serum  is  highly  bactericidal,  while  the  dog  is  very 
resistant  although  the  blood  is  slightly  bactericidal. 

Bacteriolysins  are  distinct  from  antitoxins  and  agglutinins. 
The  three  substances  may  be  distinguished  from  one  another 
by  proper  tests  even  when  they  exist  together.  The  lysin  is 
composed  of  two  substances,  the  immune  body  which  prepares 
or  sensitizes  tlie  l)acteria  and  the  complement  which  dissolves 
the  bactei'ia.  The  complement  appears  to  be  formed  by  the 
breaking  down  of  leukocytes  and  is  present  in  normal  blood. 
Although  present  in  the  blood  it  is  absent  in  the  aqueous 
humor  of  the  eye  beeause  the  latter  lacks  leukocytes.  It  is  the 
immune  body  or  amhoccpfor  which  is  specific  for  particular 
diseases  and  wliicli  is  increased  as  immunity  is  built  u]). 


138  HYGIENE  :     DENTAL    AND    GENERAL 

Hemolysis  or  the  laking  of  blood  is  the  dissolving  of  hemo- 
globin from  the  red  blood  corpuscles.  There  are  two  types 
of  hemolysins:  (1)  the  nonspecific  such  as  distilled  water, 
acids,  alkalis  and  bacterial,  plant  and  animal  toxins,  and  (2) 
the  specific  hemolysins  which  are  obtained  by  treating  or  im- 
munizing the  animal  with  the  red  blood  corpuscles  of  another 
species  of  animal.  Hemolysins  of  the  latter  type  are  similar 
to  bacteriolysins. 

It  has  been  stated  above  that  the  amboceptor  is  specific  while 
the  complement  is  nonspecific.  The  complement  fixation  test 
used  in  the  diagnosis  of  syphilis,  gonorrhea,  glanders,  per- 
tussis, meningitis  and  other  infections  is  based  on  this  prin- 
ciple. 

THEORIES  OF  IMMUNITY 

It  should  now  be  apparent  that  infectious  diseases  and 
bodily  reactions  to  these  diseases  are  widely  different  and 
that  no  simple  theory  of  immunity  can  be  satisfactory.  It 
is  therefore,  only  with  historical  interest  that  we  regard  the 
early  theories  of  Pasteur  and  Chauveau. 

Exhaustion  Theory. — In  1888  Pasteur  suggested  his  ex- 
haustion theoi'}'-  which  held  that  immunity  was  produced  be- 
cause all  the  food  substances  were  used  up.  The  one  fact  that 
bacteria  may  grow  in  the  dead  tissues  of  immune  animals 
shows  that,  during  the  life  of  the  animal,  their  growth  is  in- 
hibited by  specific  substances  and  not  by  lack  of  food. 

The  Retention  Theory. — The  retention  theory  of  Chauveau 
nuiintained  that  bacterial  growth  was  inhibited  in  disease  by 
the  retention  of  the  products  of  bacterial  metabolism.  It  is 
not  difficult  to  demonstrate  the  fallacy  of  this?  view. 

Phagocytic  Theory. — The  work  of  Metchnikoff  in  demon- 
strating the  activity  of  phagocytosis  suggested  a  possible 
mechanism  of  immunity.  It  could  be  demonstrated  that  the 
phagocytic  powci's  of  an  animal  increased  directly  with  its 
immunity  ajid  Metclmikoff:'  asserted  that  it  was  the  increased 
activity  of  tlic  white  l)l()ud  cells  M^hich  produced  innnunity. 


ESSENTIAL    FACTS    OF    IMMUNITY  139 

We  have  seen  in  the  development  of  opsonins  the  influence  of 
the  body  fluids  upon  phagocytosis. 

These  views  were  opposed  by  Ehrlich  and  other  investigators 
wlio  believed  immunity  to  be  due  mainly  to  substances  pro- 
duced in  the  body  and  set  free  in  the  body  fluids.  From  their 
point  of  view  phagocytosis  was  merely  the  process  of  getting 
rid  of  bacteria  after  they  had  been  acted  upon  by  the  immune- 
body  substances.  Metchnikoff  realized  the  existence  of  these 
substances  in  the  body  fluids  but  he  believed  them  to  be  de- 
rived from  the  leukocytes.  The  question  is  by  no  means  set- 
tled and  there  is  much  evidence  to  support  the  great  import- 
,  ance  of  phagocytes  in  bacterial  immunity. 

Side  Chain  Theory. — Every  student  of  organic  chemistry 
is  familiar  with  the  term  side  chain  as  applied  to  the  atomic 
groui^s  attached  to  the  benzol  ring.  The  graphic  formula  for 
benzene  is : 

H 

C 

II 
H-C\/C-H 

C 

H 

This  central  structure  is  possessed  by  a  large  number  of  com- 
pounds. For  example  salicylic  acid  has  the  following  formula : 

C-OH 
ll-C//\<^'-COOH 

H-C\/0-H 
C-H 

The  Oil  and  COOIT  grou])s  are  side  chains  tlirough  which 
other  substances  and  new  atomic  groups  may  enter  into  rehi- 
tionsliij)  with  the  benzol  ring. 

The  side  chain  theoi-y  of  immunity,  wliich  was  developed  by 
Ehrlich,  is  a  theory  of  chemical  side  cliains  whicli  are  attached 
— not  to  a  sim])le  ring  as  in  the  benzol  group — l)ut  to  a  central 
atom  grou})  of  tlie  large  and  complex  proteins  which  make  u]i 
cell  structures. 


140  HYGIENE  :     DENTAL    AND    GENERAL 

In  1885  Elirlicli  had  stated  his  belief  that  the  cells  of  the 
body  take  on  nutrition  through  the  reaction  of  side  chains, 
from  the  central  protein  molecules,  with  the  various  nutritive 
substances  in  the  circulating  blood.  It  seemed  reasonable  to 
him,  therefore,  that  toxin  might  exert  its  injurious  influence 
upon  the  cells  of  the  body  by  combining  with  certain  chains  of 
the  cell  protein.  Certain  of  these  side-chains  might  have  a 
specific  affinity  for  a  particular  poison.  When  this  union  had 
taken  place,  however,  the  side  chains  would  be  destroyed. 

Now  it  is  characteristic  of  nature  to  regenerate  parts  of 
tissues  which  are  lost  and  such  regenerative  processes  are  al- 
most always  carried  to  excess.  A  good  example  of  this  is  seen 
in  the  excessive  production  of  bony  substance  after  a  fracture. 
It  seemed  reasonable  that,  in  this  case,  nature  might  produce 
an  excessive  number  of  side  chains  or  receptors  under  the  con- 
tinued stimulation  and  if  this  were  done  some  of  them  would 
be  thrown  off  into  the  blood  where  they  would  be  free  to  cir- 
culate and  unite  with  the  poison  before  it  could  reach  the 
sensitive  cells.  With  such  a  substance  (antitoxin)  in  the 
blood  a  new  infection  would  not  produce  the  clinical  symptoms 
of  disease  and  the  person  would  be  immune  from  the  disease 
in  question.  This  type  of  immunity  is  spoken  of  as  immunity 
of  the  first  order  and  is  illustrated  in  the  explanatory  diagram. 

We  have  seen  that  the  body  may  possess  different  kinds  of 
immune  reactions  as  exemplified  by  the  power  of  blood  serum 
to  agglutinate  and  precipitate  such  disease  germs  as  those 
of  typhoid  fever.  The  bacterial  substance  which  injures  the 
human  body  in  this  case  is  not  a  soluble  substance,  but  a 
complex  molecule  of  the  bacterial  protoplasm.  It  seemed  to 
Ehrlich  that  the  immune  bodies  in  this  type  of  reaction  must 
be  more  complex  than  the  receptors  described  above.  Side 
chains  which  are  capable  of  handling  these  albuminous  sub- 
stances he  conceived  to  have  not  only  a  combining  (hapto- 
phore)  group,  for  anchoring  tlie  substance  to  the  body  cells, 
l)ut  also  a  ferment  (or  zymophore)  group  Avhich  could  break 
down  the  complex  molecule  after  it  was  anchored.    The  agglu- 


ESSENTIAL    FACTS    OF    IMMIXITY 


141 


^r 


.zr 


.Ara/s^/a/  (yo-// 


.£01^ 


y r i 


.2zr 


.SeK'ii^rro/  cr<r// 


SBoc-/er/o/  Ce// 


Fig.   20. — Diagram   illustrating  the   three   orders   of  immunity   as   described   in   Ehr- 
lich's   Side   Chain  Theory   of  Immunity. 

I.  Immunity  of  the  first  order.  1.  Inciting  substance  (toxin).  2.  Immune 
substance  (antitoxin).  (b)  Shows  antitoxin  which  has  been  absorbed  into 
the  blood  stream  from  the  diphtheritic  throat.  The  toxin  molecule  is  seen  ap- 
Ijroaching  the  side  chain.  (c)  By  the  excessive  production  of  side  chains  anti- 
toxin is  thrown  off  into  the  blood.  (d)  The  antitoxin  unites  with  the  to.xin  in 
the  blood   preventing   the   latter   from   attacking   the   living  cells. 

II.  Immunity  of  the  second  order.  1.  Inciting  substance  (antiagglutinin,  anti- 
precipitin,  etc  ) .  2.  Immune  substance  (agglutinin,  precipitin  «tc.).  The  immune 
substance  in  this  case  shows  a  haptophore  group  (joining  end)  and  a  zymophore 
group  (portion  containing  an  enzyme),  (a)  Bacterial  cell  with  inciting  substance  in 
the  blood  (b)  inciting  substance  about  to  combine  with  side  chain  of  body  cell, 
(c)  Free  antibody  in  the  blood  and  combination  of  incitinjr  substance  and  anti- 
body (precipitin  reaction).  (d)  Antibody  combining  with  inciting  substance  in 
the   bacterial   cell    (agglutination).' 

III.  Immunity  of  the  third  order.  1.  Inciting  substance  (anti-immune  body). 
2.  Specific  immune  body  having  a  cytophile  group  which  combines  with  the  in- 
citing substance  and  a  comidementophile  group  which  combines  with  the  comple- 
ment. 3.  Complement  or  nonspecific  immune  body  free  in  the  blood.  (a) 
Bacterial  cell  with  inciting  substance,  (b)  Inciting  substance  about  to  unite  with 
side  chain  (amboceptor).  (c)  Inuiiune  bodies  and  bacterial  cell  free  in  the 
blood,     (d)   Union  of  three  bodies  in  bacteriolysis. 


142  HYGIENE :     DENTAL    AND   GENERAL 

tinating  power  of  the  blood  of  an  immune  individual  lie  con- 
ceived to.  be  due  to  the  presence  of  these  receptors  of  the 
second  order  wliich  would  be  throwai  off  into  the  blood  under 
continued  stimulation,  like  the  antitoxin  type  of  receptor. 
This  immunitu  of  flie  seco)id  order  is  also  illustrated  diagram- 
matical] y. 

The  process  of  bacteriolysis  which  has  an  important  bearing 
on  immunity  is  of  a  different  nature  than  the  two  phenomena 
just  described.  Students  of  this  phenomenon  found  that  the 
normal  blood  of  animals  has  the  power  of  killing  certain 
disease  germs  to  a  limited  extent,  and  that  the  blood  of  specifi- 
cally immune  animals  has  the  power  of  killing  and  dissolving 
the  particular  organism  for  which  the  animal  is  immune  to  a 
great  degree.  It  was  also  learned  that  the  blood  of  an  immune 
animal  loses  this  power  upon  being  heated  to  56°C.  but  that 
the  power  is  regained  by  the  addition  of  a  little  normal  serum 
from  a  nonimmune  animal.  Reasoning  from  these  data  Ehr- 
licli  assumed  and  later  proved  to  his  own  satisfaction  that,  in 
this  type  of  immunity,  there  is  a  nonspecific  dissolving  sub- 
stance (complement)  in  the  normal  blood  which  is  able  to  act 
upon  the  bacteria  only  in  the  presence  of  and  by  combining 
with  specific  side  chains  produced  by  the  cell  proteins  in  a 
manner  similar  to  the  wa,y  the  above  mentioned  receptors  are 
produced.  The  side  chain  of  the  body  cell  in  this  third  type 
of  immunity  has  two  receptive  parts.  When  such  side  chains 
or  receptors  are  thrown  out  into  the  blood  they  unite  with 
both  the  reactive  substance  of  the  germ  cell  and  with  the  com- 
plement, which,  acting  through  these  receptors,  is  able  to  dis- 
solve the  bacterial  substances.  A  similar  reaction  takes  place 
when  the  body  is  immunized  to  foreign  blood  or  other  cells. 
Part  three  of  the  diagram  shows  the  nature  of  this  tJiird  order 
of  imniunity . 

In  all  of  the  above-mentioned  orders  the  immunizing  sub- 
stances are  supposed  to  be  produced  by  the  body  cells  and 
they  appear  in  the  blood  by  the  excessive  regeneration  of 
tliose  first  destroyed  by  the  bacterial  poison.     The  immune 


ESSENTIAL   FACTS    OP    IMJVIUNITY  143 

substances  of  the  first  order,  when  they  are  free  in  the  blood, 
arc  spoken  of  as  antitoxins,  those  of  the  second  order  are 
precipitins  or  agglutinins,  those  of  the  tliii-d  orch^r  are  called 
ainl)ocoi)tors. 

\"ang'han  lias  shown  (Protein,  iSpIit  Producis,  Lea  and  Febi- 
ger,  1913)  tliat  split  protei)i  products  from  most  proteins  will 
produce  a  fever  reaction  if  injected  into  the  body  systemati- 
cally. Such  substances  are  produced  by  almost  all  bacteria. 
It  is  a  question  whether  the  fever  reaction  produced  by  such 
organisms  as  the  typhoid  bacillus  may  not  be  due  to  these 
split  proteins  by  a  sort  of  consecutive  anaph^dactic  poisoning 
rather  than  by  specific  endotoxins. 


CHAPTER  VIII 

ORAL  PROPHYLAXIS 

In  the  chapter  on  the  Hygiene  of  the  Mouth  we  discussed 
the  normal  development  and  use  of  the  oral  structures  in 
health.  Here  we  are  concerned  with  the  prevention  of  septic 
and  disease  processes. 

Caries, — All  the  pathological  conditions  of  the  dental  pulp 
— calcareous  deposits  within  these  tissues  excepted — and  the 
series  of  morbid  processes  leading  to  the  formation  of  alveolar 


Fig.    21. — Deformity    resulting    from    neglect    of    the    teeth. 


abcess  are  due  (except  in  the  case  of  traumatic  injury)  to  the 
infection  of  this  organ  from  the  inroads  of  caries.  The  sub- 
ject of  dental  caries  has  engaged  the  attention  of  scientific 
minds  for  more  than  four  hundred  years,  and  although  much 
has  been  accomplished  towards  the  solution  of  the  problem, 
yet  it  still  affords  an  ample  field  for  laboratory  research. 

In  1530  a  German  writer  published  a  statement  so  closely 
in  accord  with  modern  findings  as  to  be  prophetic  of  the  later 
work  of  Miller  and  others.  The  following  is  a  translation 
taken  from  Black's  Operative  Dentistry. 

14i 


ORAL   PROPHYLAXIS  145 

Caries  is  a  disease  and  evil  of  the  teeth  in  wliieh  they  become  full 
of  holes  and  hollows,  which  most  often  affects  the  back  teeth;  especially 
so  when  they  are  not  cleaned  of  clinging  particles  of  food  which  de- 
compose, producing  an  acid  moisture  which  eats  them  away  and  destroys 
them  so  that  finally  with  much  pain  they  rot  away  little  by  little. 

Prior  to  the  work  of  John  Tomes,  who  gave  to  the  world  iu 
1860  the  results  of  his  microscopical  studies  of  dental  tissues, 
but  little  was  known  of  the  histological  structure  of  the  teeth, 
and  caries  was  generally  regarded  as  an  inflammatory  process, 
having  its  origin  within  the  dentin   of  the  tooth  affected. 


Fig.    22. — The    case    seen    in    Fig.    21    showing   the    malocclusion    due    to    caries. 

Tomes  found  that  the  structure  of  dentin  was  such  that  a  true 
inflammation  was  impossible,  there  being  no  circulatory  sys- 
tem, (An  exception  to  the  generally  accepted  opinion,  prior 
to  Tomes,  is  found  in  that  of  Eobertson,  who,  in  1835,  ex- 
pressed the  opinion  that  caries  resulted  from  the  action  of 
acid  due  to  the  decomposition  of  particles  of  food  retained  in 
fissures  and  imperfections  of  the  teeth.) 

In  1857  Leiber  and  Eotensteiu  in  the  course  of  experimenta- 
tion found  that  carious  dentin,  when  stained  with  iodine,  dis- 
closed within  the  tubules  granular  bodies  which  were  recog- 


14:6  HYGIENE  :     DENTAL    AND    GENERAL 

nized  as  bacteria.  This  is  the  first  record  of  the  association 
of  bacteria  as  a  cause  of  caries.  Miles  and  Underwood  in  1881 
found  that  two  factors  were  always  actiA'^e  in  caries,  namely 
(1)  the  action  of  acids,  (2)  the  action  of  germs. 

Miller  in  1882  announced  the  results  of  experiments  con- 
ducted by  him.  His  experiments  were  carried  on  with  a  view 
of  solving  the  problem  of  caries  of  dentin,  but  little  light 
was  thrown  on  the  problem  of  the  initial  lesion  in  the  enamel. 

His  conclusions  briefly  stated  are  as  follows : 

(1)  Microorganisms  are  always  present  in  the  tubules  of 
carious  dentin. 

(2)  The  invasion  of  the  tubules  is  preceded  by  decalcifica- 
tion of  the  dentin. 

(3)  The  fermentation  of  carbohydrate  foods  b,y  mouth  bac- 
teria produces  lactic  acid. 

(4)  Lactic  acid  causes  decalcification  of  the  dentin,  this 
process  being  followed  by  the  decomposition  of  the  organic 
matrix. 

Caries  of  enamel  is  undoubtedly  due  to  the  same  phenomena 
that  are  operative  in  caries  of  the  dentin.  It  differs  in  some 
particulars,  as  follow^s : 

(1)  The  original  foci  of  decay  are  generally  found  in  dis- 
tinct and  definite  locations. 

(2)  The  location  of  each  focus  of  decay  is  in  a  position 
favorable  to  the  retention  of  food  material. 

(3)  The  food  material  retained  in  this  location  in  the  pres- 
ence of  warmth  and  moisture,  affords  a  culture  medium  for 
acid  forming  bacteria. 

(4)  The  undisturbed  confinement  of  the  acid  formed  in 
the  fermentative  process  is  sufficient  to  dissolve  the  enamel. 

Why  this  carious  process  is  active  in  some  mouths  and 
passive  in  others  equally  neglected  remains  undecided.  It 
may  be  that  in  the  normal  secretions  of  some  mouths  there  are 
substances  capable  of  holding  in  abeyance  the  development  of 
bacterial  flora.  It  may  be  that  through  the  refinement  of 
food  material  and  the  development  of  epicurean  tendencies, 


ORAL   PROPHYLAXIS  147 

which  eliminate  the  necessity  for  vigorous  exercise  in  mas- 
tication, the  stimulating-  effect  upon  the  secreting  glands  with 
the  neutralizing  action  of  a  copious  flow  of  saliva  is  lost. 
Or  perhaps  the  solution  of  the  problem  lies  in  the  resistance  of 
the  enamel  itself  due  to  its  composition  and  densit^^  Slight 
imperfections  in  the  structure  of  the  enamel  are  almost  in- 
variably present,  thus  making  the  dentin  easy  of  access  to 
the  fermentative  bacteria  of  the  mouth, 

Howe  in  his  research  work  on  caries  at  the  Forsyth  Dental 
Infirmary  found  that  a  few  species  of  highly  aciduric  micro- 
organisms were  responsible  for  the  carious  process.  He  ob- 
tained these  findings  by  first  sealing  carious  cavities  with 
cement,  thus  separating  the  carious  material  from  the  flora 
of  the  mouth.  The  bacterial  cultures  were  later  secured  from 
the  layer  of  carious  dentin  which  had  been  thus  isolated. 

Although  the  problem  of  caries  has  been  seemingly  solved 
by  the  work  of  Miller  and  others,  yet  there  are  undoubtedly 
factors  related  to  the  question  of  immunity  which  are  not 
yet  understood;  and  it  may  be  that  nutrition  plays  a  larger 
part  than  we  noAV  comprehend. 

Diet  in  Relation  to  Decay. — Inasmuch  as  the  protective 
covering  of  the  teeth  is  fully  completed  at  the  time  of  erup- 
tion, too  much  stress  cannot  be  laid  upon  the  building  up  of 
these  tissues  or  upon  the  diet  of  children  up  to  the  twelfth 
or  thirteenth  3'ear.  What  constitutes  a  well-balanced  diet  is 
still  a  problem  for  research,  but  in  viewing  the  subject  from 
the  standpoint  of  common  sense  it  would  seem  that  a  study 
of  the  diet  of  the  more  primitive  races,  among  whom  normal 
development  of  the  teeth  is  practically  universal  and  who 
maintain  the  integrity  of  the  teeth  during  the  period  of  great- 
est susceptibility,  would  be  illuminating. 

The  most  universal  food  and  the  one  containing  in  itself 
all  of  the  three  nutritive  constituents,  A'iz.,  proteids,  carbo- 
hydrates and  fats,  is  milk.  Milk  is  also  the  richest  of  all 
articles  of  diet  in  the  calcium  content,  this  being  the  element 
of  greatest  importance  in  the  development  of  the  bones  and 


148  HYGIENE:     DENTAL   AND    GENERAL 

teeth.  A  liter  of  milk  contains  iy2  grams  of  lime,  which 
is  a  larger  quantity  than  is  contained  in  a  similar  amount  of 
lime  water. 

The  mineral  content  of  milk  is  sufficiently  high  to  give  it 
the  first  place  as  a  bone  building  food,  and  as  the  teeth  re- 
quire practically  the  same  elements  for  their  proper  develop- 
ment it  is  of  equal  importance  as  related  to  them.  The  infant 
requires  about  one-third  gram  of  lime  daily  and  this  amount 
is  supplied  in  milk.  A  deficiency  in  lime  may  lead  to  soften- 
ing of  the  bones  and  imperfect  development  of  the  teeth. 
Next  to  milk  come  eggs,  then  the  cereals  and  then  certain 
vegetables  such  as  carrots,  asparagus  and  spinach.  So  neces- 
sary are  these  mineral  substances  in  maintaining  the  fabric  of 
the  various  tissues  that  death  ensues  if  the  supply  is  entirely 
cut  off,  even  though  the  other  constituents  of  diet  are  sup- 
plied in  normal  amount.  The  refining  process  to  which  many 
of  the  cereals  are  subjected  in  the  manufacture  of  flour  has 
the  effect  of  depriving  the  grain  of  its  mineral  substance. 

The  mineral  content  of  foods  during  gestation  should  be 
carefully  considered  in  the  dietary  of  the  prospective  mother, 
as  the  proper  nutrition  of  the  developing  fetus  is  essential  in 
the  formation  of  enamel.  On  the  other  hand  the  development 
of  the  dentin,  cenientum  and  alveolar  process  takes  place  in 
a  large  measure  after  birth  and  continues  throughout  the  life 
of  the  individual.  Hence  proper  nutrition  in  infancy  and 
later  life  is  essential  for  the  upbuilding  of  these  tissues. 

I  would  lay  great  stress  on  the  habitual  use  at  each  meal 
of  foods  selected  not  only  on  account  of  the  nutrient  quali- 
ties, but  also  because  they  require  sufficient  masticatory  effort 
to  make  vigorous  exercise  necessary  in  the  performance  of 
this  function.  The  benefits  of  thorough  mastication  have  been 
popularized  by  Mr.  Horace  Fletcher  until  Fleteherism  has 
become  a  household  word,  and  I  am  convinced  that  the  bene- 
ficial results  are  more  far  reaching  than  even  the  most  ardent 
advocate  realizes.  In  the  first  place  there  is  an  invigorating 
effect  upon  the  supporting  structures  of  the  teeth.    Vigorous 


ORAL   PROPHYLAXIS 


149 


mastication  gives  the  necessary  stimulation  to  the  peridental 
membrane,  which  being  richly  supplied  with  blood  needs  this 
stimulation  and  functional  activity  for  the  maintenance  of 
tone.  There  is  an  increase  in  the  flow  of  saliva  and  exercise 
is  afforded  for  the  muscles  of  mastication.  The  passing  of  the 
food  materials  over  the  teeth  cleanses  their  various  surfaces 
and  massages  the  gums  and  gingives. 

The  Care  of  the  G-ums  and  Gingivae. — Black  has  divided 
the  investing  tissues  of  the  mouth  into  two  classes.     First, 


Diagrams  illustrating  nomenclature  of  gingivae.      (Black.) 

Fig.  23. — Bucoolingual  section  through  tooth  and  investins;  tissues.  .A,  Alve- 
olar process;  A''^,  Crest  of  alveolar  process;  G,  Gum;  B,  Body  of  gingiva;  F, 
Free  gingiva;   C,  Crest  of  gingiva;   Sg,   Subgingival  space. 

Fig.  24. — Mesiodistal  section  through  first  and  second  bicuspids  and  septal 
tissue.  A,  Alveolar  process;  A^,  Crest  of  alveolar  process;  B,  Body  of  gingiva; 
S,  Septal  gingiva;  C,  Crest  of  septal  gingiva  just  below  contact  point;  Sg-Sg, 
Subgingival    spaces. 


the  gums  which  clothe  the  alveolar  process  and  hard  i)alate, 
second,  the  gingivae,  which  invest  the  cervical  portions  of  the 
teeth;  it  is  the  latter  which  exercise  an  important  protective 
function  and  play  an  important  part  in  the  prevention  of 
disease ;  for  it  is  in  these  tissues  that  the  initial  injury  occurs 
Avhich,  if  neglected,  frequently  leads  to  the  infective  process 
commonly  knoAvn  as  Pyorrhea  Alveolaris. 

The  gingivae  completely  encircle  the  teeth  passing  over  the 


150  HYGIENE:     DENTAL    AND    GENERAL 

crest  of  the  septum  of  the  alveolar  process  and  rising  to  a 
point  just  below  the  contact  point  between  the  proximal  sur- 
faces of  the  teeth.  The  crests  of  the  gingiva  are  not  attached 
to  the  teeth  but  in  health  closely  hug  the  portion  which  they 
■  encircle.  The  immunity  to  decay  of  the  area  of  the  teeth 
covered  by  this  free  gingiva  is  attributable  to  the  perfection 
of  its  form  and  structure;  it  fits  closely  every  part  of  the 
tooth,  filling  the  interstices  and  guarding  the  tissues  beneath 
from  injury. 

Insufficient  study  has  been  given  to  the  function  of  these 
tissues  and  occasionally  even  the  dentist,  in  the  performance 
of-  restorative  operations  upon  the  teeth,  has  been  negligent 
in  his  care  of  these  delicate  structures.  There  can  be  no 
doubt  that  in  such  cases  he  was  responsible  for  the  initial 
injury,  which  ultimately  developed  into  a  suppurative  inflam- 
matory process  leading  to  the  destruction  of  the  investing  tis- 
sues and  to  the  eventual  loss  of  the  teeth.  The  hygiene  of  the 
gingivae  should  command  the  closest  attention  of  the  dentist, 
and  the  cooperation  of  the  patient.  In  many  cases  the  removal 
of  the  serumal  deposit  from  the  surface  of  the  tooth  immedi- 
ately under  the  free  gingiva  will  be  sufficient  to  relieve  the 
inflammation.  This  treatment  should  be  followed  at  stated 
intervals  by  gentle  massage  with  the  finger;  the  stimulation 
to  the  circulation  will  be  sufficient  to  restore  these  tissues 
to  a  normal  state  of  health  and  resistance.  The  gingivae 
should  receive  treatment  in  every  performance  of  the  toilet 
of  the  mouth  and  teeth.  Gentle  stimulation  by  proper  brush- 
ing goes  far  to  maintain  firmness  of  texture  and  freedom  from 
circulatory  congestion,  the  prime  factors  in  the  health  of  the 
supporting  structures  of  the  teeth. 

Inflammation  of  the  gingivas  frequently  is  caused  by  injury 
from  the  crowding  of  food  material  into  the  interx^roximal 
spaces  on  account  of  faulty  proximal  contact  due  to  malposi- 
tion of  the  teetli  or  loss'  of  proximal  contact  from  the  begin- 
ning of  decay.  The  impacted  food  material  first  presses  away 
the  septal  gingivae,  following  this,  putrefaction  and  fermenta- 


ORAL    IROPHYLAXIS  151 

tion  take  place.  The  soft  tissue  thus  infringed  upon  and 
injured,  loses  its  tone  and  becomes  an  easy  prey  to  the  micro- 
organisms of  infection.  When  the  septal  gingiva  is  pressed 
down  by  the  impaction  of  food  material  a  pocket  is  formed, 
and  an  infection  of  the  underlying  structures  soon  takes  place. 
The  peridental  membrane  covering  the  root  of  the  tooth  is 
invaded  and  destroyed  and  its  loss  is  followed  by  infection 
of  the  porous  cementum  covering  the  dentin  of  the  root.  In- 
fected cementum,  unlike  necrotic  bone,  will  not  separate  itself 
from  the  healthy  tissue  and  nature  has  made  no  provision  for 
its  repair  after  the  loss  of  the  peridental  membrane.  It 
therefore  becomes  a  dead  septic  area  insusceptible  to  remedial 
treatment.    . 

If  the  destruction  of  the  peridental  membrane  is  limited 
in  extent,  it  may  be  possible  by  proper  instrumentation  to 
remove  the  septic  portion  and  establish  a  new  line  for  both 
the  gum  and  peridental  membrane ;  then  by  the  exercise  of  ex- 
treme care  by  tlie  patient  and  frequent  attention  by  the  den- 
tist the  progress  of  the  destructive  process  ma}'  be  checked. 

Gingivitis. — The  early  recognition  of  the  presence  of  a 
congested  condition  of  the  gingivte  and  intelligent  remedial 
treatment  are  fundamental  in  mouth  hygiene.  Only  the  trained 
observer  will  be  able  to  do  this,  as  the  indications  are  so 
slight  as  to  elude  even  such  a  one,  unless  the  closest  examina- 
tion is  made.  These  examinations  must  include  a  study  of  oc- 
clusion, contact  points,  and  deposits.  The  removal  of  deposits 
and  the  correction  of  contact  or  the  removal  of  occlusal  strain 
will  generally  be  sufficient  to  eliminate  the  sources  of  irrita- 
tion. This  treatment  nnist  be  supplemented  by  personal  care 
on  the  part  of  the  patient  wlio  should  be  instructed  in  regard 
to  the  means  availalile  for  permanently  maintiiining  circula- 
tory activit>'  ill  these  tissues.  Back  of  ciU  this  is  tlie  function 
of  nulrition.  These  means  include  thorougli  inastication, 
]H'oper  brushing  of  the  teeth  and  massage  of  the  soft  tissue. 
Failure  to  treat  these  conditions  in  tlieir  incipiency  frequently 
ivsults  in  the  estalilislnnent   of  chronic  inflaiinnatorv  condi- 


152  HYGIENE:     DENTAL   AND   GENERAL 

tions,  disastrous  in  their  results.  Prophylactic  treatment  of 
the  gingivEe  is  as  important  as  prophylaxis  applied  to  the 
teeth. 

Deposits. — Black  has  shoAvn  that  an  excess  of  calcoglobu- 
lin  is  thrown  into  the  mouth  with  the  saliva  after  the  ingestion 
and  assimilation  of  palatable  food  eaten  of  heartily.  The 
deposits  are  paroxysmal,  occurring  at  regular  periods  after 
eating.  They  become  attached  to  any  irregular  surface  in  the 
immediate  locality  of  the  ducts  of  the  salivary  glands.  It 
was  possible  to  stop  or  produce  deposits  at  will  by  the  regula- 
tion of  diet,  eating  to  excess  always  produced  a  deposit.  The 
deposit  is  at  first  very  soft,  and  spreads  over  the  surface 
of  the  teeth.  It  may  be  easily  removed  by  careful  brushing, 
the  only  difficulty  being  the  inaccessibility  of  its  position; 
but  it  may  be  reached  if  sufficient  care  is  taken.  It  is  neces- 
sary to  explain  to  the  individual  the  usual  location  of  these 
deposits  in  order  that  he  may  intelligently  effect  their  re- 
moval. 

Another  form  of  calcareous  deposit,  which  has  been  termed 
serumal  calculus,  occurs  in  locations  inaccessible  to  the  saliva, 
the  more  common  location  being  under  the  free  margin  of  the 
gum  and  on  the  cementum  of  the  roots  of  the  teeth.  The 
deposits  are  probably  the  result  of  an  effusion  of  serum  heav- 
ily laden  with  calcoglobulin  resulting  from  inflammation  of 
the  gingival  tissues.  They  seldom  occur  in  the  mouths  of  chil- 
dren. They  are  an  additional  source  of  irritation  to  the  sup- 
porting tissues  of  the  teeth  and  should  be  removed.  As  it  is 
seldom  possible  to  prevent  their  accumulation  frequent  exam- 
ination by  the  dentist  is  necessary.  The  surfaces  of  the  teeth 
should  be  freed  from  deposit  and  polished,  great  care  being 
taken  not  to  injure  the  gingiva  or  to  detach  its  connection  with 
the  cementum  of  the  tooth.  Prophylactic  treatment  by  instru- 
mentation and  polishing  in  the  mouths  of  children  should  be 
done  with  extreme  care  and  in  many  instances  it  is  not  indi- 
cated at  all. 


ORAL    PROPHYLAXIS  153 

Prophylactic  Treatment. — The  great  benefits  to  be  de- 
rived from  prophylactic  treatment  of  the  teeth  and  gingivae 
were  first  brought  to  the  attention  of  the  dental  profession  and 
public  by  Dr.  D.  D.  Smith  of  Philadelphia,  who  was  able  to 
demonstrate  that  dental  caries  in  a  large  percentage  of  indi- 
viduals is  preventable.  His  treatment  consisted  in  frequent 
polishing  of  the  surfaces  of  the  teeth  with  suitably  shaped 
orangewood  points  impregnated  with  flour  of  pumice,  the 
points  being  held  in  a  porte-polisher.  Patients  were  required 
to  come  for  treatment  as  often  as  necessary,  this  being  in  many 
cases  w^eekly  or  bi-monthly.  Dr.  Smith  claimed  much  for  this 
treatment,  even  to  the  assertion  that  a  thorough  massage  of  the 
teeth  actually  brought  about  changes  in  the  character  of  the 
enamel,  that  enamel  became  more  dense  and  highlj^  resistant  to 
the  action  of  the  destructive  elements  within  the  mouth. 

It  is  quite  obvious  that  in  order  to  carry  out  the  regime  of 
Dr.  Smith  the  dentist  with  a  clientele  of  moderate  size  would 
be  obliged  to  devote  his  entire  time  to  the  cleansing  and  pol- 
ishing of  teeth  and  that  he  would  be  unable  to  attend  to  the 
operations  demanding  his  highest  skill.  It  followed  therefore 
that  dentists  undertaking  to  carry  out  this  polishing,  as  a 
regular  routine  in  practice,  were  obliged  to  seek  aid ;  and  the 
problem  was  finally  solved  by  training  young  women  to  act 
as  assistants. 

The  Dental  Hygienist. — The  legality  of  employing  regis- 
tered assistants  for  the  performance  of  operations  on  the  teeth 
gave  rise  to  a  controversy  within  the  profession  which  finally 
resulted  in  an  appeal  to  the  legislatures  of  the  various  states 
and  in  the  enactment  of  laws  that  placed  the  practice  of  oral 
prophylaxis  upon  a  legal  basis  and  created  a  new  and  useful 
vocation  for  women  who  are  known  as  Dental  Hygienists.  The 
work  of  a  dental  hygienist  is  carried  on  in  much  the  same  man- 
ner as  was  originally  done  by  Dr.  Smith,  some  modifications 
and  elaborations  having  been  added  since  that  time. 

Through  the  efforts  of  Dr.  A.  L.  Fo)(iies,  the  first  School  for 
Dental  Hygienists  Avas  established  in  1914.     Since  that  time 


154 


HYGIENE:     DENTAL   AND    GENERAL 


oraIj  prophylaxis  155 

several  schools  have  been  organized  and  are  now  in  operation. 
The  Forsyth  Dental  Infirmary  for  Children  has  a  training 
school  in  affiliation  with  Tufts  College  Dental  School,  and 
there  is  another  school  at  the  Rochester  Infirmary  which  was 
established  through  the  benefaction  of  Mr.  George  Eastman  of 
Kodak  fame ;  and  a  fourth  school  at  the  Dental  Department 
of  the  University  of  Minnesota. 

The  dental  hygienist  is  given  a  good  i^erspective  of  the 
field  of  dental  practice  and  is  thoroughly  trained  in  the  activ- 
ities which  she  is  to  undertake.  Not  only  does  she  clean 
and  polish  teeth  but  in  addition  she  is  able  to  assist  in  anaes- 
thesia, x-ray  work  and  the  preparation  of  patients  for  oper- 
ations. 

The  recent  and  rapid  development  of  dental  hygiene  work 
among  school  children  has  created  an  opening  for  dental  hy- 
gienists  in  the  official  health  organization  of  numy  communi- 
ties. The  young  woman  of  proper  training  and  suitable  per- 
sonality is  extremely  valuable  in  school  work  since  her 
enthusiasm  and  her  ability  to  get  on  well  with  children  es- 
pecially qualify  her  for  both  clinical  and  educational  work. 
She  examines  the  teeth  of  the  children,  fills  out  the  dental 
chart  indicating  the  defects  and  arranges  for  the  visits  to  the 
school  dental  clinic.  M^hen  the  child  arrives  for  treatment  it 
is  the  hygienist  who  all  ays  its  fears,  prepares  the  mouth  for 
treatment,  cleans  and  polishes  the  teeth  and  assists  the  dentist 
in  operative  work  if  this  is  necessary.  Instructions  in  dental 
hygiene  and  the  conducting  of  toothbrush  drills  may  devolve 
either  upon  the  Seliool  Nurse  or  the  Dental  Hygienist.  At 
present  there  are,  unfortunately,  far  too  few  graduates  in 
Dental  Hygiene  to  sui^ply  the  demand  for  such  services. 

Daily  Care  of  the  Teeth. — AVe  have  stated  that  caries  of 
the  enamel  is  largely  due  to  tiu^  retention  or  confinement  of 
food  material  in  locations  favorable  to  its  remaining  undis- 
turbed for  a  sufficient  period  of  time  for  fermentation  to 
take  place.  Tliis  being  the  cause  of  the  formation  of  cavities 
and  d(>cay,   it  is  obvious  that    if  this  food  material   can   be 


156  HYGIENE :     DENTAL   AND   GENERAL 

removed  before  the  bacteriological  action  takes  place,  tbe  dis- 
solution of  the  tooth  substance  will  be  prevented.  With  the 
most  scrupulous  care  it  is  impossible  to  entirely  prevent  caries 
in  highly  susceptible  mouths  where  it  is  very  active,  but  the 
frequency  of  occurrence  may  be  greatly  lessened.  After  five 
years '  supervision  of  the  school  children  in  the  City  of  Bridge- 
port, Fones  reports  that  caries  has  been  reduced  from  30  to  60 
per  cent  in  the  various  schools.  The  children  were  carefully 
drilled  in  the  use  of  the  toothbrush  and  home  care  was  in- 
sisted upon.  In  conjunction  with  this,  frequent  prophylactic 
treatment  by  the  dental  hygienist  was  given. 

We  believe  that  the  care  of  the  teeth  should  begin  as  soon 
as  the  child  is  put  upon  a  mixed  diet  and  even  before  this  if 
there  are  evidences  of  accretions  upon  the  surfaces  of  the 
teeth.  The  brush  should  be  of  suitable  size  to  suit  each  indi-' 
vidual  case,  not  too  large  to  pass  between  the  lip  and  cheek 
and  the  surfaces  of  the  teeth,  and  with  bristles  neither  so  stiff 
and  resistant  as  to  cut  the  soft  tissue  nor  so  soft  as  to  be  in- 
effective in  the  removal  of  soft  material.  Prior  to  use  the 
new  brush  should  be  soaked  in  boiling  w^ater.  No  definite 
method  or  rule  can  be  made  for  brushing  these  teeth.  The 
parent  or  nurse  must  take  care  that  it  is  done  thoroughly 
without  injuring  the  soft  tissues. 

Method  of  Brushing"  the  Teeth. — The  child  should  be  early 
taught  to  use  the  toothbrush  properly.  Whatever  method  is 
advocated  the  object  is  the  same,  namely  the  removal  of  all 
extraneous  material  and  the  stimulation  of  the  soft  tissues 
without  injuring  them. 

Fones  advocates  the  following  method  of  brushing : 

Place  the  toothbrush  inside  left  cheek  and  on  upper  gums,  and  nearly 
close  the  teeth  together.  Make  the  brush  go  backward  and  downward 
tc  lower  gums,  then  slightly  f oi-ward  and  upward  until  it  has  traveled 
a  complete  circle.  This  circular  motion  should  be  done  rapidly  so  that 
the  gums  will  be  stimulated  and  the  teeth  cleansed  of  food. 

Keep  up  this  fast  circular  motion  and  brush  all  the  teeth  on  the 
left  side  as  well  as  all  of  the  front  teeth.  Do  not  brush  the  teeth  and 
gums   crosswise. 


ORAL   PKOPHYLAXiS  157 

Now  brush  the  riglit  side  with  tlie  same  circular  motion  or  reversing 
the  circle  if  found  more  convenient.  Brush  long  enough  to  thoroughly 
stimulate  the  gums  and  cleanse  the  teeth,  going  back  and  forth  over 
all  the  surfaces  several  times. 

With  the  bristles  of  the  brush  pointing  upward  and  the  end  of  the 
thumb  on  the  back  of  the  handle,  bnash  the  roof  of  the  mouth  and  the 
inside  gums  and  surfaces  of  the  teeth  with  a  fast  in-and-out  stroke, 
reaching  back  on  the  gums  as  far  as  you  can  go.  Go  back  and  forth 
across  the  roof  of  the  mouth  with  this  in-and-out  stroke  at  least  four 
times. 

Hold  the  handle  of  the  toothbrush  in  your  fist  with  the  thumb  lying 
across  the  back  of  the  handle  and  brush  the  gums  and  teeth  with  an 
in-and-out  stroke,  using  chiefly  the  tuft  end  or  toe  of  the  brush.  Reach 
Ijack  in  the  mouth  on  ,the  gums  below  the  last  tooth  on  both  sides  and 
bi-ush  with  a  fast,  light,  in-and-out  stroke.  Tip  the  handle  of  the 
brush  up  in  brushing  the  gums  back  of  the  lower  front  teeth. 

Lastly,  brush  the  teeth  with  an  in-and-out  stroke  on  the  surfaces 
on  which  you  chew,  as  the  food  must  be  removed  from  the  gi'ooves  or 
fissures  of  the'  molars. 

The  writer  prefers  tlie  following  method  described  by 
Black  in  the  chapter  on  Mouth  Hygiene  in  his  Special  Dental 
PatJiology.  Beginning  with  the  left  side  of  the  lower  jaw, 
after  the  brush  has  been  moistened  in  water  or  normal  salt 
solution  and  lime  water,  the  end  should  be  carried  back  to  the 
last  molar  or  beyond  when  possible.  The  ends  of  the  bristles 
of  the  brush  should  be  placed  against  the  gums  over  the  roots 
of  the  teeth.  Then  with  either  a  straight  or  twisting  motion  of 
the  wrist  the  brush  should  be  swept  over  the  teeth  toward  their 
occlusal  surfaces.  This  should  be  done  several  times.  The 
same  procedure  should  be  repeated  with  the  right  side. 

For  the  upper  jaw  the  brush  is  placed  far  back  on  the  gum 
first  on  the  left  side.  The  bristles  are  swept  over  the  gingivae 
and  teeth  in  the  direction  of  the  occlusal  surfaces.  The  same 
procedure  is  used  for  the  right  side.  Particular  attention 
is  called  to  the  fact  that  the  motion  of  the  brush  is  first  over 
the  gums,  next  over  the  gingivae  and  next  over  the  buccal 
surfaces  of  the  teeth  to  the  occlusal  margins.  Then  the  brush 
is  lifted  and  replaced  upon  the  gums  as  before  and  again 
swept  over  the  gingivae  and  teeth. 


158 


HYGIENE  :     DENTAL    AND    GENERAL 


The  motions  for  the  lingual  surfaces  of  the  lower  molars 
should  be  practically  the  same  as  those  for  the  buccal  sur- 
faces but  they  are  more  difficult  to  make  correctly.  The  same 
may  bo  said  for  the  lingual  surface  of  the  upper  molars.  In 
brushing  of  the  lingual  surfaces  of  the  incisors  the  handle 
of  the  brush  should  project  out  of  the  mouth  parallel  to  the 
length  of  these  teeth.  The  brush  held  in  this  position  should 
be  placed  on  the  gum  and  the  motion  of  the  brush  should  be 


Fig.  26. — Tooth  brushes  of  proper  shape  and  material  are  made  in  different 
sizes  for  children  and  adults.  The  cut  shows  such  tooth  brushes  exactly  one-half 
normal   size. 


over  the  gum,  gingivae  and  teeth.  The  brush  should  then  be 
lifted  and  replaced  on  the  gum  and  the  motion  over  the  gum, 
gingivre  and  teeth  repeated  several  times.  The  brush  may  be 
moved  from  side  to  side  across  the  lingual  surface  of  the 
teeth  close  to  the  gum  for  removal  of  deposits  which  may  have 
been  missed  by  the  other  movements.  This  brushing  should 
include  the  gum.  The  occlusal  surface  of  the  teeth  should  also 
be  thoroughly  brushed. 


**  ORAL   PROPHYLAXIS  15!) 

The  teeth  should  he  brushed  with  sufficient  frequency  to 
prevent  the  fermentation  of  food  with  the  formation  of  acid. 
Four  times  a  day  has  been  advocated,  once  after  each  meal  and 
before  retiring  at  Jiiglit.  The  time  of  greatest  importance 
is  before  retiring;  for  in  sleep  the  muscular  tissues  of  the 
mouth  are  at  rest  and  the  oral  secretions  greatly  lessened, 
thus  affording  the  most  favoral)le  opportunity  for  undisturbed 
action  of  the  acid-forming  bacteria.  This  final  brushing 
should  never  be  n|glected.  The  danger  of  infection  of  the 
soft  tissues  of  the  mouth  by  proper  brushing  is  so  slight  as 
to  be  practically  negligible. 

Care  of  the  Brush. — As  the  result  of  experiments  to  de- 
termine the  most  hygienic  method  of  caring  for  the  brush 
the  authors  have  found  that  a  brush  rinsed  in  water  after 
using  and  then  placed  in  a  closed  receptacle  developed  many 
more  bacteria  than  one  which  was  rinsed  in  hot  water  and  left 
in  the  air  to  dry.  It  is  therefore  advised  that  the  brush  be 
thoroughly  rinsed  in  Jiot  water  after  each  use.  The  brush 
should  be  freed  from  water  as  much  as  possible  by  shaking 
and  then  hung  in  the  air  in  a  place  protected  from  the  dust. 

Dental  Floss. — The  use  of  dental  floss  is  to  remove  any 
particle!^  that  may  remain  upon  the  proximal  surfaces  of  the 
teeth  after  brushing  or  after  eating  when  it  is  not  possible 
to  brush  the  teeth.  The  silk  should  be  passed  through  the 
contact  points  and  held  closel}^  to  the  surface  of  the  teeth 
and  carried  upward  or  downward  as  far  as  the  gingivae. 
Care  must  be  taken  or  injury  will  be  done.  If  the  contact 
point  is  close,  the  force  used  may  result  in  the  sudden  passage 
of  the  floss  and  carry  it  against  the  soft  tissues  so  roughly 
as  to  cause  damage. 

Toothpicks. — The  toothpick  is  also  used  to  clean  the 
proximal  surfaces  of  the  teeth  after  eating.  An  orangewood 
pick  with  a  smooth  flat  blade  or  a  quill  is  to  be  preferred 
and  care  should  be  taken  not  to  injure  the  soft  tissues  or 
push  the  gingivtc  away  from  the  surfaces  of  the  teeth.  Too 
often  people  l)lindlyand  violently  thrust  the  toothpick  be- 


160  HYGIENE:     DENTAL   AND   GENERAL 

tween  the  teeth,  in  an  attempt  to  relieve  some  slight  irrita- 
tion, until  actual  bleeding  of  the  gums  is  produced.  Another 
vicious  and  unsightly  habit  is  the  prolonged  use  and  chewing 
of  the  cheap  wooden  toothpick  from  which  splinters  are  de- 
tached to  irritate  the  membranes  of  the  mouth  and  throat. 
The  toothpick  should  be  used  privately,  not  publicly. 

Mouth  Washes,  Tooth  Powders  and  Pastes. — Prinz  states 
that  the  sterilization  of  the  oral  cavity  by  any  antiseptic 
which  can  be  employed  with  safety  is  impossible.  This  being 
the  case,  the  use  of  commercial  preparations  advertised  to  do 
this  is  not  only  useless  but  may  be  harmful,  and  their  use 
should  be  condemned. 

We  have  shown  that  the  saliva  possesses  many  of  the  de- 
sirable qualities  of  a  mouth  wash.  The  ideal  mouth  wash 
should  be  of  a  similar  nature,  with  the  addition  of  a  bacteri- 
cidal property.  The  qualities  of  the  mouth  wash  should  be 
such  that  it  will  not  irritate  the  soft  tissues,  that  it  will  not 
destroy  the  salivary  ferments,  that  it  will  be  bactericidal, 
that  it  is  not  poisonous  if  swallowed.  The  wash  should  be 
readily  available  and  inexpensive  so  that  it  may  be  used 
freely  and  without  harm.  The  writer  has  for  many  years  ad- 
vised the  use  of  salt  and  water  for  this  purpose.  Prinz  has 
shown  that  physiologic  salt  solution  reduced  the  oral  flora  by 
50  per  cent,  and  he  advises  the  use  of  this  solution  with  the 
addition  of  half  an  ounce  of  lime  water  to  eight  ounces  of  a 
salt  solution.  The  lime  water  is  mildly  astringent  and  is  a 
solvent  of  mucinous  material.  Fones  advocates  the  use  of 
lime  water  alone,  and  states  that  five  cents  worth  of  coarse 
unslaked,  lime  such  as  the  masons  use  for  coarse  plaster  will 
keep  a  family  supplied  with  the  best  kind  of  mouth  wash  for 
a  whole  year. 

Tooth  powders  are  largely  used  as  an  aid  in  mechanically 
cleansing  the  surfaces  of  the  teeth.  Much  injury  may  result 
from  the  use  of  an  abrasive  material  and  only  the  finest  pre- 
cipitated calcium  carbonate  should  be  used  for  this  purpose. 
This  may  be  combined  with  a  small  amount  of  soap  and  sac- 


ORAL   PROPHYLAXIS  161 

charine  and  flavored  with  one  of  the  essential  oils.  A  suitable 
powder  may  be  made  by  thoroughly  mixing  a  half-pound  of 
finest  grade  English  precipitated  chalk  with  three  grains  of 
finely  powdered  saccharine,  a  half-ounce  of  powdered  castile 
soap  and  50  to  100  drops  of  oil  of  wintergreen  or  peppermint. 

Pastes  are  made  by  adding  gelatine  or  glycerine  to  the 
powder. 

Tooth  Cleansing-  Foods. — The  use  of  slightly  acid  fruit 
as  the  last  article  of  food  to  be  eaten  in  a  meal  is  to  be  com- 
mended for  its  efficacy  in  the  removal  of  sticky  particles  of 
food  and  its  stimulating  effect  upon  the  salivary  glands, 
thereby  promoting  a  free  flow  of  saliva  which  quickly  neutral- 
izes the  acid.  The  lunch  which  the  child  carries  to  school 
should  contain  an  apple  or  an  orange  for  dessert  instead  of 
the  jam,  cookies  and  sweets  so  often  used. 

Care  of  the  Mouths  of  Children. — It  is  of  the  uttermost 
importance  that  the  growing  child  should  be  taken  to  the 
dentist  for  frequent  examination.  Beginning  at  the  age  of 
three  years  a  careful  inspection  should  be  made  at  least  every 
three  months.  This  inspection  should  include  not  only  an  ex- 
amination for  cavities  of  decay,  which  should  be  immediabcly 
treated  or  filled,  but  also  a  study  of  the  dental  archea  to  de- 
termine whether  normal  development  is  taking  place.  Slight 
stimulation  by  properly  directed  but  gentle  force  may  be  neces- 
sary to  bring  this  about.  If  retarded  development  is  dis- 
covered early,  very  little  interference  is  necessary  to  stimulate 
growth  but  if  neglected  the  consequences  may  be  serious.  The 
treatment  of  incipient  caries  by  the  dentist  by  the  use  of  ni- 
trate of  silver  will  frequently  inhibit  decay,  and  the  necessity 
for  filling  the  deciduous  teeth  may  be  avoided. 

Septic  Teeth  as  a  Source  of  Systemic  Disease. — During 
the  past  five  years  much  has  been  written  on  this  subject  and 
investigators  of  prominence  both  in  medicine  and  dentistry 
have,  after  exhaustive  research,  arrived  at  conclusions  so 
similar  as  to  justify  the  statement  that  in  a  variable  per- 
centage of  persons  suffering  from  lesions  of  the  kidneys,  heart 


162  HYGIENE:     DENTAL   AND    GENERAL 

and  joints,  x-ray  and  bacterial  examination  will  reveal  the 
presence  of  septic  foci  around  the  roots  of  one  or  more  teeth. 
The  removal  of  these  teeth  is  often  followed  by  marked  im- 
provement of  the  general  symptoms. 

Kosenow  {Journal  of  Dental  Research,  Vol.  8,  No.  3,  Sept., 
1919)  states,  that  the  number  of  persons  suffering  from  dis- 
eases directly  attributable  to  dental  foci  of  infection  as  well  as 
from  nonrelated  conditions  which  have  been  cured  or  bene- 
fited by  elimination  of  foci  of  infection,  in  various  branches 
of  medicine,  is  so  large  as  to  be  quite  sufficient  to  prove  the 
general  truth  of  the  idea  of  causal  relationship.  He  advises 
the  removal  of  all  nonvital  teeth  in  persons  suffering  from 
arthritis,  heart  or  kidney  affections,  and  some  other  forms  of 
disease  for  which  other  causes  cannot  be  found.  It  is  easy 
to  see  the  possibility  of  an  infection  spreading  from  the  region 
of  the  mouth  to  other  parts  of  the  body;  but  we  believe  that 
the  number  of  cases  attributed  to  this  cause  is  greatly  over- 
estimated. Cases  are  on  record  showing  an  undoubted  re- 
lationship between  systemic  infection  and  dental  foci  by  the 
marked  improvement  produced  by  the  elimination  of  the  dis- 
eased teeth.  But  to  act  upon  the  hypothesis  that  diseased 
teeth  represent  the  sole  cause  of  these  systemic  diseases  and 
to  advise  wholesale  removal  of  useful  organs,  is  entirely  un- 
warranted. Certainly  teeth  should  never  be  removed  merely 
because  no  cause  for  systemic  disease  is  apparent.  This  is 
a  matter  in  which  the  dentist  must  take  an  independent  stand 
and  his  knowledge  of  dental  pathology  should  be  sufficient  to 
enable  him  to  determine  whether  or  not  extractions  should  be 
made,  whatever  may  have  been  the  prescription  of  an  attend- 
ing physician.  There  is  no  excuse  for  the  indiscriminate  ex- 
traction of  useful  teeth. 

Taking  the  opposite  point  of  view  from  that  of  Cotton, 
Rosenow,  Hartzell  and  others,  Howe  states  that  "a  focus  of 
infection  is  a  localized  pathological  area  in  which  bacteria 
are  to  be  found.  Here  the  process  is  centralized  and  if  the 
forces  of  immunity  are  unimpaired,  the  bacteria  if  not  actu- 


ORAL   PROPHYLAXIS  1G3 

ally  destroyed  are  walled  off  from  the  rest  of  the  human 
system,  moreover,  the  individual  attains  a  liigh  and  specific 
immunity  against  this  specific  morbid  process.  Bacteria  are 
not  discharged  freely  into  the  circulation  to  wander  at  will 
and  to  settle  without  rhyme  or  reason  at  any  point  they 
choose.  Once  they  enter  the  blood  they  are  easily  disposed  of 
by  all  the  forces  of  immunity. ' ' 

While  this  statement  seems  a  sane  viewpoint,  especiall}^ 
so  when  the  comparative  minuteness  of  the  septic  area  in- 
volved in  the  chronic  alveolar  abscess  is  considered,  yet  the 
degree  of  acquired  immunity  to  any  given  organism  may  be 
variable  or  even  lost,  and  it  is  in  the  period  of  lowered  re- 
sistence  that  the  possibility  of  systemic  infection  is  present. 

Were  this  not  the  fact,  the  danger  of  general  septicemia 
from  infective  processes  in  any  part  of  the  bodj^  would  be  neg- 
ligible. That  this  is  not  the  case  is  amply  proven  by  clinical 
experience,  and  by  the  fact  that  the  first  surgical  law  in  the 
treatment  of  any  abscess  is  the  establishment  of  drainage. 
That  there  is  an  element  of  danger  in  the  presence  of  oral 
septic  conditions  would  seem  to  be  implied  by  Dr.  Howe's 
statement  that  "all  oral  septic  conditions  should  be  cleared 
up."  Better  still  would  be  the  statement  that  septic  oral 
conditions  should  be  prevented. 

There  is  some  evidence  that  certain  types  of  insanity  are 
produced  by  abnormal  mouth  conditions.  It  is  perfectly  rea- 
sonable to  make  a  distinct  connection  between  the  disturbances 
of  the  mental  equilibrium  and  a  local  condition  where  pres- 
sure upon  the  nerves  is  exerting  a  constant  zone  of  irritation 
such  as  an  impacted  condition  of  the  teeth.  This  is  undoubt- 
edl}'^  shown  in  the  nervous  manifestations  which  occur  during 
the  period  of  dentition  in  childhood.  It  is  much  easier  to  con- 
ceive of  neuroses  being  related  to  conditions  of  impaction  than 
to  understand  how  they  can  be  related  to  conditions  of  infec- 
tion as  some  medical  writers  believe.  Cotton  says  that  "in 
about  25%  of  the  cases  of  the  functional  types  and  dementia 
precoxia  groups,  foci  of  infection  in  the  teeth  alone  are  the 


164  HYGIENE:     DENTAL   AND   GENERAL 

etiological  factor,  and  extraction  of  the  affected  teeth  is  fol- 
lowed by  complete  recovery."  Corroboration  from  many 
sources  would  seem  necessary  before  accepting  such  a  sweep- 
ing statement  and  one  so  far  reaching  in  its  effects. 

The  fact  that  the  loss  of  the  vitality  of  the  dental  pulp 
through  the  inroads  of  caries  and  the  infected  organic  matter 
contained  in  the  tubuli  of  the  dentin  is  the  primary  cause 
of  a  very  large  percentage  of  these  foci  at  once  suggests  the 
possibility  of  the  absolute  prevention  of  these  serious  sys- 
temic conditions  by  hygienic  measures. 

While  it  may  not  be  possible  to  prevent  the  formation  of 
cavities  of  decay  in  the  teeth  which  may  eventually  infect 
the  dental  pulp  and  lead  to  its  death,  yet  careful  regard  of 
the  principles  of  hygiene  and  the  reinforcing  of  the  protective 
agencies  supplied  by  Nature,  proper  attention  to  diet  and  the 
exercise  of  the  function  of  mastication  will  be  effective  to  a 
surprising  degree. 

In  view  of  the  possible  far  reaching  effect  of  dental  dis- 
ease it  becomes  the  prime  function  of  the  dentist  to  instruct 
those  coming  under  his  care  in  such  a  way  as  to  make  clear 
the  measures  at  hand  for  the  prevention  of  dental  caries. 


CHAPTER  IX 

C0MMUNICABLJ3  DISEASES 

Three  Great  Plagues. — Diseases  which  are  spread  because 
of  the  existence  of  unsanitary  conditions  have  been  rapidly 
brought  under  control,  but  the  diseases  which  are  spread 
largely  by  personal  contact  have  not  been  correspondingly  re- 
duced. Perhaps  no  illustration  is  better  than  the  communi- 
cable disease  history  of  the  army  during  the  four  last  wars. 
We  may  show  graphically  how  the  number  of  disease  deaths 
have  declined  in  relation  to  the  number  of  battle  deaths. 
This  is  a  remarkable  achievement  but  it  is  chiefly  an  achieve- 
ment of  sanitation.  Intestinal  and  insect  borne  fevers  have 
been  almost  eliminated.  On  the  other  hand  the  respiratory 
disease  rate  remains  very  high.  •  Pneumonia  caused  13  per 
cent  of  the  deaths  of  the  Civil  War  and  but  3  per  cent  of  the 
deaths  in  the  Spanish  War.  But  in  the  recent  war  it  was  a 
dread  disease  and  caused  85  per  cent  of  all  deaths  from  dis- 
ease, liaving  a  death  rate  of  over  9  per  thousand.  If  the 
respiratory  diseases  had  been  eliminated  from  our  army  in 
the  world  war  the  army  disease  death  rate  would  have  been 
practically  that  of  the  civilian  population. 

In  civil  life  as  well  as  in  warfare  the  diseases  transmitted 
by  mouth  and  nose  secretions  present  a  great  unsolved  prob- 
lem. It  is  not  our  purpose  to  consider  here  the  detailed  path- 
ology or  the  administrative  methods  of  control  for  tlie  various 
communicable  diseases.  Appendix  A  contains  a  brief  but 
comprehensive  summary  of  the  public  health  facts  regarding 
them.  There  are  however,  three  diseases  or  groups  of  diseases 
which  are  of  paramount  importance  to  society  and  which 
particularly  interest  the  dental  practitioner  because  they  are 
communicable  and  because  the  infective  organisms  are  found 

165 


166 


HYGIENE:     DENTAL   AND    GENERAL 


in  the  oral  cavity.  We  may  refer  to  these  diseases  in  popular 
language  as  the  Great  Red  Plague,  the  Great  White  Plague 
and  the  Great  Pandemic.  They  are  syphilis,  tuberculosis,  and 
common  cold.     Progress  can  be  made  against  these  scourges 


disease: 


DISEASE 


BATTLE 


BATTLE 


BATTLE 


25 


33 


DISEASE 


BATTLE 


DISEASE 

I 


53 


Itexlcan  Var 

Civil  War 

Spanish  War 

PRESEHT  WAB 

1846-48 

(Horth) 

1898 

to  New  11 

1861-65 

1918 

Fig.  27. — Comparative  figures  showing  the  number  ot  disease  and  battle 
deaths  each  year  i)er  thousand  troops  in  the  wars  of  the  L'niited  States.  (United 
States   Army    figures.) 


only  by  a  broad  and  almost  universal  knowledge  of  their 
nature,  their  seriousness,  transmission  and  the  methods  by 
which  they  may  be  combated. 


COMMUNICABLE   DISEASES 


167 


TUBERCULOSIS 

Prevalence. — Descriptions  of  tuberculosis  may  be  found 
in  the  earliest  medical  writings.  It  has  always  been  an  impor- 
tant disease.  It  is  the  most  wide  spread  of  all  infections  and 
correspondingly  the  greatest  single  cause  of  the  death.  At 
least  9  per  cent  of  all  deaths  are  due  to  this  disease.     Ten 


-.3% 


MCASLES 

5CARLCT  FEVCR^ 


ORGAniC  HfARTOI5E:A5E^-4% 

APPEMDICITIS —AX 

PERITON/TIS   -5 

TYPHOID    .55?)— I 

BRIGHT^  DISEASE 

5EPTCEMIA   

EMPYEMIA  


Fig.  28. — The  relative  proportion  of  army  deaths  caused  by  the  principal  diseases 
in    the    war   with    Germany.      (United    States    Army    figures.) 

million  of  tlic  people  now  living  in  this  country  will  die  of 
tuberculosis  and  yet  it  is  a  preventable  disease ;  we  know  its 
cause  and  we  know  how  it  maj^  be  prevented.  It  is  most  un- 
fortunate that  tuberculosis  is  a  disease  of  young  people  and 
carries  away  its  victims  in  the  prime  of  life  at  the  height  of 
their  earning  and  productive  capacity. 


168  HYGIENE :     DENTAL   AND    GENERAL 

It  has  been  estimated  that  the  number  of  cases  of  tuber- 
culosis in  any  community  is  approximately  10  times  the  num- 
ber of  annual  deaths  from  the  disease.  That  is,  if  a  town  has 
50  deaths  from  tuberculosis  in  1920  it  probably  has  500  active 
cases.  This  figure  has  been  confirmed  by  the  recent  tuber- 
culosis experiments  conducted  by  the  Metropolitan  Life  Insur- 
ance Company  in  the  city  of  Framingham,  Massachusetts. 
When  this  work  was  started  there  were  three  known  cases  of 
tuberculosis  per  annual  death  in  the  city.  Large  blocks  of  the 
population  including  thousands  of  people  have  received  physi- 
cal examinations  during  this  health  experiment  and  a  tuber- 
culosis expert  has  been  provided  who  gives  free  consultation 
to  the  practicing  physicians.  The  present  figures  show  9  cases 
of  active  tuberculosis  and  11  cases  of  arrested  tuberculosis  per 
annual  death. 

The  Difficulties. — Why  is  it  that  the  Great  White  Plague 
continues  to  take  its  annual  toll  in  lives  of  our  people  while 
typhoid  is  being  rapidly  banished  from  our  country?  The 
following  are  some  of  the  difficulties  in  combating  tubercu- 
losis : 

(1)  The  disease  is  transmitted  by  contact  and  therefore  has 
not  the  same  direct  relation  to  sanitation  as  does  typhoid 
fever. 

(2)  There  is  no  way  of  producing  an  artificial  immunity 
by  the  use  of  vaccine,  and  there  is  no  satisfactory  method 
of  serum  treatment.  The  reaction  of  the  body  to  tuberculosis 
is  cellular  and  not  antitoxic.  Instead  of  producing  a  chemical 
substance  to  combat  the  organism  the  body  walls  off  the  tu- 
bercle bacilli  by  the  white  blood  cells  and  encapsulates  them 
by  the  cells  of  the  connective  tissues.  To  be  sure,  the  body 
becomes  sensitized  or  anaphylactic  from  the  first  infection  so 
that  it  may  react  more  promptly,  but  since  the  reaction  de- 
pends upon  cell  activity  the  bodily  resistance  depends  upon 
the  vitality  of  the  individual  and  not  upon  a  chemical  sub- 
stance. 


COMMUNICABLE   DISEASES  169 

(3)  Bodily  vigor  which  makes  it  possible  to  resist  tuber- 
cular infection  is  impossible  of  universal  attainment.  It  is 
very  simple  to  say  that  fresh  air,  nourishing  food,  and  suf- 
ficient sleep,  will  prevent  or  cure  incipient  tuberculosis  but 
these  very  simple  things  are  just  what  many  people  are  un- 
able to  secure.  Under  the  economic  basis  of  society  it  is  not 
possible  for  everyone  to  have  healthy  work,  sufficient  recre- 
ation in  the  open  air,  and  a  suitable  diet. 

(4)  The  disease  is  so  benign  and  its  onset  so  gradual  that 
society  is  not  aroused  against  it.  A  tuberculosis  patient  is 
often  cheerful  up  to  the  very  day  of  his  death  and  there  is 
nothing  startling  or  terrible  about  the  first  stages  of  the  dis- 
ease. If  tuberculosis  were  accompanied  by  a  high  fever  and 
a  disagreeable  rash  as  is  smallpox,  then  rapid  progress  would 
be  made  in  its  elimination  but  as  it  is,  we  somehow  conclude 
that  because  it  is  common  it  is  not  dangerous  in  spite  of  the 
fact  that  1  out  of  12  of  our  acquaintances  will  probably  die 
with  this  preventable  disease. 

Transmission  of  Tuberculosis. — It  is  to  be  remembered 
that  there  are  two  strains  of  organisms  which  produce  this 
disease,  the  human  and  the  bovine,  and  that  there  are  many 
types  of  the  disease,  although  phthisis  or  tuberculosis  of  the 
lungs  is  the  most  common  form.  Many  other  parts  of  the 
body  are  attacked  including  the  bones,  the  meninges  and  the 
glands. 

Glandular  infections  among  children  are  very  common  and 
a  large  percentage  of  such  infections  are  with  the  bovine 
strain.  It  has  been  stated  that  from  one-fourth  to  one-third 
of  the  tuberculosis  in  children  under  five  years  of  age  is 
caused  by  the  bovine  type  of  bacillus  which  is  probably  in- 
gested with  cow 's  milk.  Eecent  hospital  records  show  the  bo- 
vine bacillus  to  be  the  cause  of  80  per  cent  of  the  glandular 
cases  in  children  under  4  years  of  age  and  the  cause  in  100 
per  cent  of  such  cases  in  children  under  one  year  of  age. 
Records  from  a  large  number  of  cervical  gland  operations  in 
children  show  that  65  per  cent  of  gland  infections  were  tuber- 


170  HYGIENE:     DENTAL   AND   GENERAL 

culous  and  in  90  per  cent  of  these  the  organism  was  the  bovine 
type.  Infection  is  therefore  possible  both  from  man  and  from 
animals  and  may  be  acquired  both  by  inhalation  and  inges- 
tion. 

The  chief  source  of  infectioD  from  man  is  the  sputum  and 
it  was  formerly  thought  that  the  organism  was  most  commonly 
acquired  by  being  breathed  into  the  lungs  in  droplets  sprayed 
into  the  air  by  the  cough  of  the  tuberculous  patient  or  in  the 
form  of  dust.  This  type  of  infection  does  take  place.  Cornet 
was  able  to  infect  47  out  of  48  guinea  pigs  exposed  to  the  dust 
produced  by  sweeping  a  carpet  which  had  been  purposely  in- 
fected with  tuberculous  sputum  but  this  was  an  unusual  con- 
dition and  the  dose  of  the  infection  was  great.  Moreover  the 
continual  breathing  of  dust  irritates  the  lungs  and  makes  it 
easier  for  the  bacillus  to  gain  a  foothold.  But  although  in- 
fection by  inhalation  does  occur  we  have  probably  overesti- 
mated the  importance  of  this  method  in  the  past. 

We  have  recently  come  to  regard  more  seriously  the  prob- 
ability of  infection  through  ingestion.  The  opportunities  for 
infection  in  this  manner  are  countless  and  it  has  been  shown 
that  the  organism  may  make  its  way  from  the  throat  and 
tonsils  to  the  glands  of  the  neck  and  from  the  small  intestines 
to  the  abdominal  glands,  to  the  lungs  and  other  parts  of  the 
body.  No  doubt  the  presence  of  decayed  teeth  and  infected 
tonsils  makes  it  easier  for  the  bacilli  to  multiply  in  the  body 
by  providing  acceptable  lodgings  in  the  mouth  and  throat  and 
by  reducing  bodily  resistance. 

We  must  accordingly  recognize  the  danger  of  tuberculosis 
infections  from  contact  in  any  of  the  various  ways  by  which 
the  infectious  material  from  a  tuberculous  patient  may  reach 
our  mouths.  It  may  be  that  we  handle  infected  material  and 
then  carry  the  fingers  to  the  mouth  or  it  may  be  that  the  in- 
fection is  carried  by  milk,  flies,  cups,  handkerchiefs,  or  other 
articles.  This  danger  should  make  us  more  careful  of  food 
sanitation. 


COMMUNICABLE   DISEASES  171 

The  number  of  bacteria  taken  into  the  body  is  important 
as  it  has  been  shown  that  men  and  experimental  animals  can 
resist  a  limited  amount  of  infection.  In  fact  investigators 
assert  that  almost  every  individual  who  has  lived  to  the  age 
of  25  or  30  years  will  show  tubercular  lesions  at  autopsy,  al- 
though they  may  never  have  developed  clinical  symptoms  of 
the  disease.  It  seems  therefore  that  everyone  must  receive 
tubercle  bacilli.  The  question  of  whether  we  have  tubercu- 
losis or  not  depends  upon  the  size  of  the  dose  and  our  degree 
of  natural  immunity,  which  in  this  case  is  directly  related  to 
general  health. 

Tuberculosis  is  not  hereditary  although  it  is  possible  that 
some  predisposition  to  it  ma}^  be  inherited.  Of  course  if  the 
child  is  taken  care  of  by  a  tuberculous  mother  there  is  great 
opportunity  for  early  infection. 

The  disease  may  indeed  be  spread  through  contaminated 
water  supplies.  Sputum  which  has  not  been  disinfected  fre- 
quently finds  its  way  into  the  sewer  and  the  feces  themselves 
contain  tubercle  bacilli.  These  organisms  are  enclosed  in  a 
little  fatty  sheath  and  are  therefore  more  resistant  to  cold 
water  than  many  other  organisms  and  it  seems  reasonable  to 
believe  that  they  may  be  present  in  a  polluted  water  suppl}^, 
especially  since  the  vital  statistics  of  various  cities  have  shown 
a  reduced  amount  of  tuberculosis  when  the  water  supplies 
were  improved. 

Prevention  and  Control. — We  have  in  our  hands  many 
woapon.3  for  combating  the  disease  which  we  are  not  always 
using  to  the  best  advantage.  Some  of  these  may  here  be  de- 
scribed. 

1.  Education. — In  order  tliat  our  campaign  may  succeed  the 
people  must  understand  the  facts  and  the  seriousness  of  the 
disease.  Fortunately  the  message  is  a  hopeful  one  because 
tuberculosis  is  curable.  The  public  should  know  this  but  it 
should  also  know  that  it  is  transmissible.  Many  infections 
could  be  avoided  by  better  personal  prophylaxis  if  people 
would  insist  upon  good  ventilation,  refuse  to  use  common 


172  HYGIENE:     DENTAL   AND   GENERAL 

drinking  cups  or  unpasteurized  milk  from  cattle  which  are  not 
tuberculine  tested  and  if  they  would  avoid  intimate  associa- 
tions with  cases  of  tuberculosis.  Much  could  be  done  also  by 
securing  a  desire  for  wholesome  diet  and  by  removing  mechan- 
ical obstructions  to  breathing  and  other  predisposing  factors. 

2.  Segregation. — Much  can  be  gained  by  separating  the  tu- 
berculous patient  from  uninfected  individuals.  Hospitals 
should  be  provided  for  the  advanced  eases  and  sanatoria 
should  be  available  for  the  incipient  cases.  There  is  a  prac- 
tical difficulty  here,  for  hospitals  and  sanatoria  are  expensive 
and  it  is  not  always  possible  to  persuade  the  individual  most 
needing  the  treatment  to  accept  it.  We  have  been  particu- 
larly lacking  in  sanatoria  where  the  middle  classes  of  society 
could  receive  treatment  at  a  reasonably  low  cost.  The  legal 
power  to  forcibly  remove,  isolate,  restrain  and  keep  under 
treatment  the  irresponsible  and  incorrigihle  consumptive  is 
needed  for  the  welfare  of  the  community. 

3.  Home  Treatynent. — Even  if  enough  sanatoria  could  be 
provided  there  are  often  disadvantages  in  removing  a  patient 
from  his  home  and  it  is  fortunate  that  so  much  can  be  done 
b}^  home  treatment  if  it  is  properly  carried  out.  Dispensaries 
should  be  provided  in  every  community  for  the  diagnosis, 
treatment  and  instruction  of  the  consumptive.  If  this  phase 
of  the  work  is  properly  conducted  any  case  may  receive 
prompt  and  early  diagnosis  and  may  be  taught  how  to  avoid 
infecting  other  people.  Something  may  be  done  to  secure 
better  housing  conditions,  a  more  suitable  type  of  work  and  an 
improvement  of  diet.  If  the  patient  will  honestly,  intelli- 
gently, and  'conscientiously  obey  instructions  he  may  have 
every  hope  of  improving  his  condition  in  his  own  home,  pro- 
vided the  disease  is  not  too  far  advanced,  and  he  will  probably 
do  better  in  mind  and  body  if  his  home  is  not  broken  up.  If 
the  patient  is  unintelligent  or  incorrigible  there  is  little  hope 
for  his  recovery  under  any  consideration  and  society  must 
safeg-uard  the  health  of  the  people  who  Avould  be  brought  in 
contact  with  liiin  and  endangered  by  his  carelessness. 


COMMUXICABLE   DISEASES 


173 


4.  Thherculosis  Societies. — The  National,  State  and  Local 
Societies  for  the  Prevention  of  Tuberculosis  are  important 
factors  in  combating  the  spread  of  the  disease.  What  is  every- 
body's business  is  nobody's  business  and  it  is  altogether  too 
easy  for  the  governmental  agencies  to  neglect  obviously  needed 
activities  for  safeguarding  the  health  of  its  citizens.  Often 
the  health  official  would  like  to  do  more  but  careless  and  un- 


Fig.    29. — An   inexpensive    and    easily    constructed    outdoor    sleeping   porch. 

informed  public  sentiment  will  not  support  him.  Fortunate 
is  the  community  which  has  a  group  of  interested  citizens  or 
an  individual  who  can  organize  the  necessary  campaign  for 
disease  control.  Successful  campaigns  of  this  type  usually 
involve  certain  definite  steps.  The  press,  the  physicians,  the 
politicians,  the  Chamber  of  Commerce,  the  business  interests 
of  various  groups  must  first  be  aroused  and  interested ;  then 
a  local  committee  is  formed  and  a  tuberculosis  exhibit  is  se- 


174  HYGIENE:     DENTAL   AND    GENERAL 

cured  from  tlie  National  Society  for  tlie  Prevention  of  Tuber- 
culosis or  from  the  State  Board  of  Health.  A  local  tubercu- 
losis society  is  formed,  a  dispensary  is  established  with  a 
physician  and  nurse  in  charge  and  then  a  day  camp  may  be 
provided.  The  municipal  authorities  are  usually  ready  to 
take  over  the  work  at  this  point  and  carry  it  on  with  whatever 
additions  and  improvements  may  be  necessary. 

SYPHILIS 

Venereal  diseases  present  what  some  public  health  workers 
regard  as  our  most  important  health  problem  and  yet  little 
was  done  in  an  official  way  for  their  scientfic  prevention  pre- 
vious to  the  last  decade.  In  one  of  the  three  venereal  diseases 
(syphilis)  mouth  lesions  are  very  common  and  the  dentist 
may  have  to  M-ork  upon  infected  individuals.  But  we  wish 
the  dentist  to  appreciate  the  social  as  well  as  the  professional 
aspects  of  the  disease  and  we  shall  therefore  treat  both  phases 
of  the  question. 

Importance. — Syphilis  did  not  appear  in  the  civilized 
world  until  1493.  There  is  evidence  {Journal  American  Med- 
ical Association,  June  12,  1915,  Vol.  LXIV,  24,  p.  1962)  that 
it  was  carried  to  Europe  by  the  crew  of  Columbus  on  the  re- 
turn of  his  first  voyage.  By  those  members  of  the  crew  who 
joined  the  army  of  Charles  VIII  of  France  it  was  carried  in- 
to Italy  with  the  invasion  of  that  country  for  the  conquest 
of  Naples  in  1494.  The  epidemic  which  began  there  rapidly 
spread  over  all  Europe  with  the  most  serious  consequences, 
for  the  disease  was  then  new  and  its  course  was  extremely 
rapid  and  severe. 

The  seriousness  of  this  disease  has  not  been  realized  because 
its  existence  has  been  hidden.  Until  recently  the  only  accu- 
rate data  which  we  have  had  regarding  the  presence  of  the 
disease  were  secured  from  military  organizations.  It  has  been 
easy  to  conceal  the  presence  of  the  disease  in  civil  life  because 
the  infected  individual  is  not  physically  incapacitated  during 


communicabIjE  diseases  175 

its  early  stages.  Kober  {Transactions  Association  Amancan 
Physicians,  Philadelphia,  1911,  Vol.  XXVI,  p.  155)  gives  a 
table  showing  the  prevalence  of  the  disease  in  certain  military 
groups  for  specific  years. 

Differentiated  Infections  Per  Thousand  Men 

Year  Syphilis   Chancroid  Gonorrhea  Total 

U.   S.   Army 1909  30.45  30.77  135.77  196.99 

U.  S.  Navy 1909  26.49  28.23  105.11  159.83 

Japanese    Navv 1907         139.75 

British    Navy." 1908  37.46  17.87  67.16  122.49 

British  Army 1908  35.1  28.23  40.7            75.8 

Japanese   Army 1907  10.1  10.4  17.1            37.6 

Prussian    Army 1907         4.4  2.1  12.2            18.7 

The  variations  of  this  table  as  well  as  more  recent  figures 
from  our  own  army  indicate  that  much  may  be  done  to  limit 
the  amount  of  infection.  The  following  figures  are  t-aken  from 
a  statement  of  Colonel  P.  M.  Ashburn,  contained  in  Report 
of  Hearings  (H.  R.  5123)  Excluding  Advertising  of  Cures  for 
Venereal  Diseases  from  the  Mails. 

Army  Venereal  Incidence  Eate  per  1,000  for  Preceding  Years 

tear  rate  year  rate 

1911  163.49  1914      110.69 

1912  136.70  1915     107.71 

1913  99.22  1916     103.35 

1917  113.82 

Incidence  in  Camps  during  War  per  1,000 60 

Incidence  in  A.  E.  F.  during  War  per  1,000 45 

We  have  recently  learned  more  about  the  venereal  diseases 
in  civilian  as  well  as  military  life.  That  venereal  disease  con- 
trol is  a  civilian  as  well  as  a  military  problem  is  shown  by  Dr. 
W.  A.  Sawyer,  Major  M.C., U.S.A.  (American  Journal  of  Puh- 
lic  Health,  May,  1919)  who  states  the  result  of  special  reports 
rendered  by  Camps  Upton,  Dix,  Meade,  Lee  and  Pike  for  a 
period  of  21  weeks  from  March  29,  1918  to  November  15,  1918. 
Taking  these  five  camps  together  the  annual  venereal  disease 
rate  for  the  entire  period  was  347.88  per  thousand  men.  The 
rate  for  eases  contracted  in  civil  life  and  recorded  as  of  the 


176  HYGIENE:     DENTAL    AND    GENERAL 

date  when  first  discovered  was  336.96,  while  the  rate  for  cases 
contracted  after  enlistment  was  only  10.92.  Less  than  %o 
of  the  42,032  cases  in  these  camps  were  contracted  after  en- 
listment. jVIajor  Sawyer  believes  that  for  all  the  troops  in 
this  country  including  the  organizations  that  had  been  longer 
in  the  service  than  the  newly  drafted  men  mentioned  above 
five  to  one  was  a  close  estimate  of  the  ratio  between  the  cases 
contracted  before  enlistment  and  those  contracted  afterwards. 

In  spite  of  prompt  isolation,  thorough  and  proper  medical 
treatment,  the  compulsory  use  of  prophylactic  stations,  the 
elimination  of  prostitution  so  far  as  possible  in  the  region  of 
camps  and  a  thorough  educational  program,  there  was  a  loss 
to  the  army  representing  2,195,000  days  of  service  between 
April  1917  and  September  1918  {United  States  PuMic  Health 
Service  Reports,  Oct.  24, 1919).  However,  even  in  the  absence 
of  specific  records  we  may  be  certain  that  this  is  a  relatively 
slight  time  loss  compared  with  that  of  previous  M^ars. 

Some  idea  of  the  more  serious  effects  of  syphilis  are  found 
in  a  study  of  ]\Iattauschek  (Jledicinische  Klinik,  1913,  Vol. 
IX,  p.  1544)  who  investigated  4,134  cases  of  the  disease  occur- 
ring among  officers  of  the  Austrian  Army  between  1880  and 
1900.  Of  these  officers  14.64  per  cent  were  dead  or  disabled 
as  a  result  of  the  disease.  Of  this  group  20  had  died,  198  had 
severe  paresis,  113  had  locomotor  ataxia  and  132  had  cerebro- 
spinal syphilis,  80  of  whom  were  insane. 

But  these  figures  do  not  tell  the  whole  story  because  the 
disease  although  hidden  from  the  public  greatly  reduces  the 
vitality  of  its  victims  and  an  early  death  is  likely  to  occur 
from  a  variety  of  other  causes.  Very  few  of  the  insurance 
companies  will  accept  syphilitics  as  risks  and  even  those  com- 
panies which  accept  cases  after  thorough  treatment  usually 
refuse  to  carry  the  individual  after  55  years  of  age. 

The  effects  of  this  disease  upon  the  offspring  are  perhaps 
more  serious  than  the  effects  upon  the  diseased  parents.  The 
active  disease  may  be  inherited  from  either  the  father  or  the 
mother ;  or  serious  defects  may  be  transmitted  to  the  offspring 


COMMUNICABLE   DISEASES  177 

because  of  the  presence  of  the  disease  poison.  These  more 
frequently  manifest  themselves  in  serious  abnormalities  of  the 
nervous  system. 

Nature  of  the  Disease. — When  an  infection  is  produced 
]jy  Treponema  pallidum  there  first  occurs  a  hard  indurated 
ulcer  or  chancre  in  the  skin  or  mucous  membrane  at  the  site 
of  the  initial  infection.  But  the  spirochetes  soon  invade  the 
whole  system  and  the  second  stage  of  the  disease  is  marked 
by  fever,  anemia,  the  involvement  of  lymph  nodes,  and  erup- 
tions upon  the  skin  and  mucuous  membranes.  The  mucous 
patches  in  the  mouth  appear  at  this  time  and  the  disease  is 
highly  infectious.  During  the  third  stage  of  the  disease  local- 
ized granulomatous  growths  (gummata)  appear  in  the  various 
organs  of  the  body  and  it  is  following  this  stage  that  the 
serious  effects  upon  the  central  nervous  system  are  produced. 

Transmission. — The  spirochete  of  syphilis  has  been  shown 
(Zinser  and  Hopkins:  Journal  American  Medical  Association, 
Vol.  LXII,  p.  23,  June  6,  1914)  to  persist  on  a  moist  towel 
for  111/4  hours.  It  does  not  resist  dryness  and  will  not  grow 
after  having  been  dried  on  a  slide  for  one  hour.  It  is  a  rela- 
tively frail  organism  but  of  such  Adability  as  to  be  transmitted 
in  other  ways  than  through  sexual  approach.  In  fact  ac- 
cidental infections,  contracted  outside  of  venery,  are  more 
commo)i  than  is  ordinarily  supposed.  Even  a  slight  scratch  in 
the  skin  is  sufficient  to  permit  the  introduction  of  the  virus 
as  has  often  been  demonstrated  by  infections  upon  the  hands 
of  surgeons  and  in  the  practice  of  midwifery.  It  is  possible 
for  the  disease  to  be  transmitted  by  kissing,  or  by  the  use  of 
oommon  drinking  cups  or  common  towels.  Dental  instru- 
ments, the  barber's  razor,  pipes,  spoons,  or  glasses,  may  con- 
vey the  infection  if  proper  precautions  are  not  used.  This 
possibility  for  innocent  infection  makes  the  disease  a  menace 
to  every  member  of  the  communitj^  because  syphilis  is  present 
in  every  class  of  the  social  scale. 

Immunity. — There  is  an  immunity  conferred  upon  a  non- 
syphilitic  fetus  by  the  syphilitic  mother  and  an  immunity 


178  HYGIENE:     DENTAL   AND   GENERAL 

conferred  upon  the  nonsypliilitie  mother  by  the  syphilitic 
fetus.  The  first  condition  was  long  ago  set  forth  by  Prof  eta's 
Law  which  holds  that  a  healthy  child  will  not  contract  syph- 
ilis from  nursing  a  syphilitic  mother.  The  other  principle 
is  known  as  Baume's  or  Colles'  Law  which  asserts  that  a  syph- 
ilitic child  born  of  a  healthy  mother  will  infect  the  most 
healthy  nurse  but  not  its  own  mother.  There  is  no  natural 
immunity  to  syphilis. 

Prevention. — A  study  of  the  methods  of  control  enumer- 
ated for  this  disease  in  Appendix  A  will  show  that  we  have 
recently  made  a  good  deal  of  progress  in  combating  the  mal- 
ady. The  emergency  of  war  allowed  the  inception  of  a  gen- 
eral campaign  against  it.  Now  the  people  as  well  as  the  physi- 
cians and  health  officers  realize  that  the  venereal  diseases  must 
be  treated  like  all  other  contagious  diseases  if  they  are  to  be 
eliminated.  Consequently  it  has  been  possible  to  establish 
measures  to  secure  the  reporting  of  cases,  and  their  continued 
treatment.  Aided  by  the  Chamberlain-Kahn  Bill,  which  pro- 
vided conditionally  for  the  distribution  of  $1,000,000  among 
the  State  Boards  of  Health  each  year  for  the  two  fiscal  years 
beginning  July  1,  1918  together  with  other  appropriations  for 
activities  within  the  Bureau,  the  U.  S.  Public  Health  Service 
has  conducted  its  campaign  against  venereal  diseases  by  assist- 
ing in: 

1.  Securing  prompt  reporting. 

2.  Carrying  on  repressive  measures. 

3.  Establishing  free  clinics  for  treatment. 

4.  Carrying  on  a  general  educational  campaign. 

Forty-six  states  (all  but  Pennsylvania,  Nevada  and  the 
District  of  Columbia)  adopted  the  regulations  necessary  to 
obtain  their  quota  of  Federal  money  for  the  first  year.  This 
involved  the  establishment  of  a  special  Department  or  Di- 
vision of  Venereal  Diseases  and  the  institution  of  proper  con- 
trol regulations.     It  is  to  be  hoped  that  this  disease  will  in 


COMMUNICABLE   DISEASES  179 

the  future  receive  the  attention  it  deserves  from  healtli  author- 
ities and  be  handled  like  other  communicable  diseases. 

An  idea  of  the  treatment  facilities  furnished  by  the  U.  S. 
Public  Health  Service  and  the  State  Boards  of  Health  may 
be  obtained  from  the  following  summary  of  the  July  report 
{PuUic  Health  Report,  September  5,  1919).  During  this 
period  131  clinics  were  operated  and  for  the  month  5,624  new 
eases  of  venereal  diseases  were  admitted  making  a  total  of  16,- 
871  under  treatment.  A  total  of  61,578  treatments  were  ad- 
ministered to  patients  and  10,952  of  these  individual  treat- 
ments v.'ere  the  administration  of  arsphenamine.  There  were 
discharged  as  cured,  314,  as  non-infectious  but  not  cured,  244, 
as  probably  cured,  893.  Altogether  during  the  10  months — 
October  1918  to  July  1919 — over  230,000  cases  were  treated  at 
the  267  United  States  Public  Health  Service  and  State  Clinics 
which  reported.  Many  other  cases  were  treated  but  not  re- 
ported. 

Educational  ProgTam. — Perhaps  the  educational  work 
carried  on  during  the  war  was  the  most  important  part  of  the 
campaign  because  after  all  the  continuation  of  suitable  ad- 
ministrative measures  depends  upon  the  support  of  the  com- 
munity. We  have  already  indicated  in  our  discussion  of  sex 
hygiene  that  the  young  man  or  the  young  woman  should  be 
told  of  the  danger  of  venereal  diseases  at  the  right  time  and  in 
the  right  way.  This  can  now  be  more  easily  done  than  in  the 
past.  The  Public  Health  Service  and  State  Departments  of 
Health  have  prepared  special  and  admirable  pamphlets  for 
different  groups  and  ages.  During  the  war  the  motion  picture 
"Fit  to  Fight"  prepared  speciallj'  for  men  in  the  service  was 
shown  to  practically  every  man  in  the  army  and  na^y.  Since 
then  this  picture  and  others  like  "The  End  of  the  Road"' 
have  been  shown  to  a  large  percentage  of  our  civil  population. 
These  films  have  been  well  made  and  if  shown  under  the  right 
auspices  they  are  useful  and  instructing  to  young  men  and 
women.  They  can  best  be  shown  under  the  supervision  of 
the  State  or  Federal  Government,  in  which  case  the  picture 


180  HYGIENE:     DENTAL   AND    GENERAL 

may  be  preceded  by  a  talk  from  a  physician  or  health  officer 
to  make  certain  that  the  audience  approaches  the  subject  in 
the  right  frame  of  mind.  It  is  doubtful  whether  such  films 
should  ever  be  shown  without  being  under  the  supervision  of 
some  medical  or  health  officer.  It  is  not  proposed  to  use  these 
pictures  for  boys  or  girls  under  16  years  of  age. 

The  public  should  learn  from  these  sources  that  syphilis  is 
a  conununicable  disease,  that  its  presence  can  be  determined 
by  clinical  examination  or  by  the  Wassermann  laboratory  test 
upon  the  blood  serum.  The  disease  is  now  curable  by  the  use 
of  salvarsan  and  allied  products  but  the  course  of  treatment 
must  extend  over  three  years  and  must  be  followed  out 
honestly  and  completely.  The  best  doctors  insist  that  the 
marriage  of  syphilitics  should  never  be  sanctioned  unless  they 
have  undergone  three  years  of  thorough  treatment  and  have 
subsequently  been  without  symptoms  for  at  least  one  year. 
Prophylaxis  with  calomel  ointment  within  20  hours  after  ex- 
posure is  a  fairly  successful  but  not  a  certain  preventive 
against  the  disease. 

We  may  hope  that  the  serious  consideration  which  has  been 
given  this  disease  in  the  United  States  during  the  past  few 
years  will  give  health  authorities  a  keener  appreciation  of  the 
seriousness  of  the  problem,  that  it  will  make  the  medical  and 
allied  professions  more  aware  of  their  responsibility  in  warn- 
ing the  patient  against  the  spread  of  the  disease  and  in  keep- 
ing him  under  treatment  until  the  disease  is  cured,  and  that 
the  general  public  will  understand  the  facts  regarding  the 
disease  and  insist  that  the  practical  and  common  sense  medical 
and  legal  measures  shall  be  taken  for  its  control, 

COMMON  COLD 

It  may  seem  strange  that  the  common  cold  should  be  listed 
here  as  the  third  great  health  problem  but  a  moment's  con- 
sideration will  show  that  it  is  the  most  widespread  of  the  com- 
municable diseases.     It   is    continuously   pandemic.     Always 


COMMUNICABLE   DISEASES  181 

and  everywhere  the  common  cold  is  present  to  a  limited  ex- 
tent and  certainly  no  contagious  disease  enters  the  dentist's 
office  so  often  as  this  one.  We  pay  little  attention  to  the  dis- 
ease because  it  is  not  fatal  and  there  are  no  good  figures  to 
show  us  what  a  tremendous  loss  it  really  produces. 

Let  us  consider  merely  the  economic  loss  from  this  disease. 
Is  it  not  safe  to  assume  that  the  average  workman  loses  two 
days  a  year  from  a  coldf  If  this  is  true  then  thirty  million 
people  who  are  employed  in  industry  lose  a  total  of  sixty  mil- 
lion days  work.  If  you  reckon  the  average  wage  as  $4.00  a 
day  here  is  nearly  a  quarter  of  a  billion  dollars  lost  in  wages 
alone.  Add  to  that  the  cost  of  decreased  production  and  the 
loss  from  throwing  out  of  employment  other  people  in  the 
same  department  or  depending  upon  the  work  of  the  absentee 
and  the  loss  becomes  truly  appalling.  And  this  does  not  take 
into  consideration  the  loss  of  efficiency  during  the  days  when 
the  individual  works  with  a  cold  or  the  general  impairment  of 
health  which  colds  produce;  and  the  figures  are  for  factory 
workers  only. 

Are  we  justified  in  saying  that  common  cold  is  not  a  serious 
disease  merely  because  it  does  not  produce  death  ?  The  com- 
mon cold  is  an  acute  infection  of  the  nose,  pharynx,  tonsils, 
larynx,  trachea  or  upper  bronchi ;  and  how  often  do  neuritis, 
rheumatic  fever,  pneumonia  and  rapidly  progressing  organic 
diseases  follow  these  conditions! 

The  Cause  of  Colds. — The  cold  is  an  infection  and  not 
merely  a  congestion.  It  is  contagious  and  runs  through  a 
family  or  through  a  school  or  through  a  group  of  workers 
just  as  any  other  infectious  disease.  It  has  not,  however,  a 
single  cause.  There  are  a  variety  of  bacteria  associated  with 
catarrhal  infections  such  as  staphylococci,  streptococci,  pneu- 
mococci,  the  influenza  bacillus,  the  diphtheroid  bacillus  and 
the  bacillus  catarrhalis.  Many  of  these  bacteria  are  normal 
inhabitants  of  the  mouth  and  nasal  passages  and  they  are 
doubtless  waiting  for  an  opportunity  to  set  up  the  disease 
anew  when  the  vitality  of  the  indi"\ddual  is  lowered. 


182  HYGIENE:     DENTAL   AND   GENERAL 

Catching  Cold. — Many  people  still  have  the  mistaken  be- 
lief that  drafts  produce  colds.  Of  themselves  drafts  cannot 
produce  infections  and  a  chill  is  not  the  time  when  the  in- 
fection takes  place  but  rather  indicates  the  period  when  the 
cold  is  becoming  more  active.  When  a  cool  wind  reaches  the 
skin  of  a  normal  individual  his  vasomotor  system  reacts  by 
removing  the  blood  from  the  skin  and  thereby  lessening  the 
heat  lost  and  the  body  further  reacts  by  increasing  the  heat 
production,  RemoAdng  the  blood  from  the  skin  about  the 
face,  shoulders  and  back  of  the  head  will  congest  the  blood 
vessels  at  the  interior.  This  may  increase  the  watery  or  serous 
exudate  upon  the  inner  surfaces  of  the  throat  and  nasal  pas- 
sages, and  bacteria,  which  may  be  present  normally  or  which 
have  been  recently  acquired,  find  an  opportunity  to  develop 
rapidly  on  these  congested  surfaces.  Furthermore  if  the  cool- 
ing effect  is  long  continued  the  temperature  of  the  body  is 
reduced  and  in  this  way  the  resistance  is  lessened.  If  the 
vasomotor  system  of  the  body  is  in  poor  condition  bodily  ad- 
justments to  changes  in  temperature  are  less  efficient  and 
drafts  are  more  likely  to  produce  injurious  effects.  It  is  by 
improving  the  vasomotor  system  that  cold  baths,  physical 
exercise  and  vigorous  health  assist  in  keeping  a  person  free 
from  common  cold. 

Conditions  which  cause  a  continual  irritation  in  the  nose 
and  throat  also  predispose  to  colds.  Chronic  catarrh,  en- 
larged tonsils,  polypus,  deviation  of  septum  and  adenoids  are 
examples.  No  doubt  a  dirty  mouth  is  more  likely  to  harbor 
the  bacteria  which  may  produce  common  cold  than  a  clean 
mouth.  The  quality  of  the  air  passing  over  the  respiratory 
passages  is  also  important.  Poor  ventilation  which  allows  the 
air  to  become  too  dry  or  dusty  will  set  up  undesirable  nose 
and  throat  irritation.  The  air  should  be  fresh  and  of  suitable 
temperature.  If  the  home  or  work  place  is  too  warm  the  sud- 
den change  of  going  out  into  the  open  will  congest  the  breath- 
ing passages.  It  has  been  pointed  out  that  in  the  coldest 
weather  it  is  the  passengers  in  the  stuffy  carriages  of  the  train 


COMMUNICABLE   DISEASES  183 

who  catch  cold  and  not  the  fireman  and  engineer.  Arctic 
explorers  have  been  free  from  colds  while  in  the  far  north 
only  to  become  reinfected  by  a  return  to  temperate  climate 
where  reinfection  took  place. 

Since  the  organisms  which  produce  cold  are  almost  con- 
stantly in  the  mouth  and  nose  the  opportunities  for  infection 
are  innumerable.  Dr.  Chapin  has  stirred  the  imagination  by 
asking  us  to  consider  what  would  be  the  result  if  the  secre- 
tions from  the  mouth  and  nose  were  of  a  bright  color.  If 
each  individual  shed  from  these  cavities  a  different  shade  of 
an  intense  red  dye  it  would  be  appalling  to  see  how  quickly 
the  surroundings  would  take  on  a  rosy  hue.  The  fingers  are 
constantly  going  to  the  mouth  and  nose  and  would  quickly 
become  a  deep  red  color.  The  handkerchief  would  become 
quickly  dyed,  we  would  exchange  material  with  the  people 
with  whom  we  shake  hands  and  the  door-knobs,  trolley  car- 
straps,  our  desks,  books,  and  instruments  would  all  acquire 
the  color  far  too  rapidly.  Perhaps  it  would  be  fortunate  if 
this  could  happen  to  us  for  a  day.  We  would  certainly  have 
a  revelation  as  to  the  amount  of  care  which  we  should  use  in 
preparing  and  serving  our  food,  and  we  might  wish  to  abolish 
the  habit  of  hand  shaking. 

There  are  three  important  rules  for  the  prevention  and 
treatment  of  colds : 

(1)  Remember  that  colds  are  spread  by  organisms  in  the 
secretions  of  the  nose  and  throat,  and  try  to  avoid  infection. 
We  should  be  much  more  careful  in  avoiding  contact  with 
persons  who  have  colds.  We  should  not  let  people  cough  or 
sneeze  in  our  faces  and  we  should  avoid  using  common  eating 
or  drinking  utensils.  We  must  educate  or  train  ourselves  in 
habits  of  sanitation  or  cleanliness  as  those  words  are  inter- 
preted under  the  germ  theory  of  disease. 

(2)  Avoid  predisposing  causes.  Drafts,  poor  food,  extreme 
fatigue,  lack  of  sleep,  and  bodily  defects  lower  the  resistance 
of  a  person  so  that  colds  may  be  acquired  more  readily.     Do 


184  HYGIENE  :     DENTAL    AND    GENERAL 

not  neglect  the  duty  to  yourself  of  keeping  in  good  physical 
condition. 

(3)  When  you  feel  a  cold  coming  on  go  to  hed.  This  may 
seem  a  severe  remedy  but  there  are  many  reasons  for  doing  it. 
Colds  are  most  contagious  during  the  early  period  and  if  a 
person  isolates  himself  in  bed  he  is  preventing  contagion  as 
well  as  taking  the  best  possible  care  of  himself.  The  recon- 
structive forces  of  the  body  work  best  when  a  person  is  resting 
quietly  in  bed  under  proper  conditions  of  temperature  and 
nutrition.  The  body  is  rested  and  strengthened  and  the  dan- 
ger of  increasing  the  severity  of  the  disease  by  exposure  to 
cold,  damp  and  fatigue  is  eliminated.  To  stay  in  bed  for  a 
day  or  two  when  a  cold  is  first  coming  on  is  perhaps  the  best 
economy  of  time  as  well  as  a  "safety  first"  procedure, 

INFLUENZA 

In  1890  the  United  States  had  a  severe  epidemic  of  la  grippe 
or  influenza.  There  were  milder  recurring  epidemics  during 
the  next  three  years  and  since  that  time  (prior  to  1918)  we 
have  thought  of  influenza  as  a  mild  endemic  disease.  There 
was  a  fatality  rate  of  about  one  death  in  a  thousand  cases. 
"We  have  found  the  influenza  bacillus  in  what  seemed  like  com- 
mon colds,  and  we  have  spoken  of  the  "grippe,"  "grippy 
colds ' '  and  ' '  bad  colds ' '  rather  indiscriminately. 

In  1918  there  began  an  epidemic  of  influenza  which  proved 
to  be  the  most  serious  epidemic  in  the  history  of  the  world. 
The  first  cases  of  the  great  epidemic  in  America  were  brought 
to  Boston  on  an  army  transport  late  in  the  month  of  August 
and  from  this  city  the  disease  rapidly  spread  to  all  parts  of 
the  country.  During  the  winter  of  1918  and  1919  there  were 
nearly  a  half  million  deaths  in  the  United  States  attributable 
to  this .  disease.  The  influenza  was  frequently  complicated 
with  pneumonia  and  it  v-as  in  this  complication  that  the  death 
rate  was  highest.  Instead  of  losing  one  out  of  every  thousand 
persons  ivlio  liad  the  disease  during  this  epidemic  we  lost  about 


COMMUNICABLE   DISEASES  185 

five  persons  for  every  thousand  people  of  our  wliole  popula- 
tion. It  is  reported  that  in  India  there  were  five  million 
deaths. 

Cause. — It  Avas  particularly  difficult  to  combat  because 
we  did  not  and  we  still  do  not  know  the  cause.  The  influ- 
enza bacillus  was  found  in  a  large  percentage  of  the  cases  but 
it  seemed  to  many  that  there  must  be  some  other  microor- 
ganism present.  If  the  disease  was  due  to  the  influenza  ba- 
cillus alone  the  germ  possessed  a  virulence  of  incomparably 
greater  strength  than  that  of  the  organism  which  has  been 
present  in  the  endemic  form  of  the  disease.  Endemic  influ- 
enza has  presented  much  the  same  problem  as  do  common 
colds.  Epidemic  influenza  has  presented  an  entirely  new 
group  of  problems.  It  may  be  well  to  summ.arize  some  of  the 
facts  which  have  been  brought  to  light  from  our  recent  sad 
experience. 

Morbidity  and  Mortality  Rates. — Classifying  the  45  cities 
of  the  Weekly  Health  Index  into  three  broad  geographical 
groups  the  Census  Bureau  found  a  variation  in  the  mortality 
{Weekly  Health  Index,  March  1,  1917).  In  the  cities  east  of 
the  Appalachians  the  mortality  from  pneumonia  and  influ- 
enza from  September  14,  1918,  to  March  1,  1919,  was  approx- 
imately 5.6  per  thousand ;  in  cities  between  the  Eocky  Moun- 
tains and  the  Appalachians  4.35  per  thousand ;  and  in  those 
of  the  Pacific  Coast  5.55  per  thousand.  There  were,  however, 
Avide  differences  among  individual  cities. 

To  gather  further  statistics  house  to  house  surveys  Avere 
made  by  the  Public  Health  Service  from  the  f olloAving  popula- 
tion groups ;  NcAV  London,  Conn.,  7,993 ;  Baltimore,  Md.,  33,- 
361 ;  certain  smaller  tOAvns  and  rural  districts  in  Maryland, 
12,669;  Spartanburg,  S.  C,  5,257;  Louisville,  Ky.,  12,602; 
Little  Rock,  Ark.,  9,920;  San  Antonio,  Texas,  12,534;  San 
Francisco,  Cal.,  18,682. 

The  case  incidence  Avas  highest  in  children  from  5  to  14 
years  old  and  progressively  loAver  in  each  higher  age  group. 
The  ratio  of  pneumonia  cases  to  total  population  varied  from 


186  HYGIENE :     DENTAL   AND    GENERAL 

6.3  per  thousand  in  Spartanburg,  S.  C,  to  24.6  per  thousand  in 
the  smaller  towns  of  Maryland.  The  pneumonia  rate  showed 
little  correlation  with  the  influenza  attack  rate.  The  ratio  of 
deaths  to  population  varied  from  1.9  per  thousand  in  Spartan- 
burg to  6.8  in  Maryland.  The  death  rate  was  by  no  means 
parallel  to  the  influenza  attack  rate  but  was  closely  correlated 
to  the  pneumonia  attack  rate.  The  fatality  from  pneumonia 
was  uniformly  about  30  per  cent  except  in  San  Antonio,  where 
it  was  only  18.5  per  cent.  The  death  rate  was  notably  higher 
in  children  under  one  year  old,  in  adults  from  20  to  40,  and 
in  persons  over  60  ;  higher  in  males  than  in  females  and  higher 
in  the  white  than  the  colored  population. 

Immunity. — Some  investigators  believe  there  is  a  con- 
siderable but  not  absolute  immunity  conferred  by  an  attack  of 
the  disease.  In  Baltimore  the  first  canvass  was  made  prior  to 
December  11  and  a  second  canvass  was  made  in  January. 
Among  32,600  people,  724  cases  were  found  to  have  occurred 
since  the  previous  survey.  Upon  an  investigation  of  cases  the 
clinical  diagnosis  of  influenza  in  both  attacks  was  conflrmed 
in  only  26  cases,  or  0.37  per  cent  of  the  total  and  even  in  these 
cases  the  diagnosis  was  necessarily  uncertain.  It  will  be  seen, 
however,  that  there  was  a  very  brief  period  between  these 
studies  and  the  author  believes  that  other  figures  will  soon  be 
available  to  indicate  that  no  lasting  immunity  is  conferred  by 
an  attack  of  the  disease. 

Control. — An  important  investigation  by  Col.  Lynch  and 
Lieut. -Col.  Cumming  (American  Journal  of  Public  Healtli, 
Jan.,  1919)  indicates  clearly  that  influenza  may  be  spread  by 
a  contamination  of  eating  utensils  which  are  not  properly 
boiled  in  washing.  The  investigators  compared  two  groups 
of  troops  living  under  comparable  conditions  except  that  in 
the  first  group  the  mess  kits  were  collected  and  properly 
washed  in  boiling  water  while  in  the  second  group  there  was 
individual  mess  kit  washing  in  water  which  was  necessarily 
below  the  boiling  point.  These  two  groups  were  about  equal 
in  size.     In  the  group  having  collective  tableware  washing 


COMMUNICABLE   DISEASES  187 

there  were  33,452  men,  among  whom  there  occurred  1710 
cases  or  a  period  rate  of  51.1  cases  per  thousand  for  the  14 
days  under  consideration.  Among  the  second  group  of  ap- 
proximately the  same  size,  where  there  was  individual  mess 
kit  washing,  there  were  8208  cases  or  a  period  rate  of  252. 
It  was  shown  that  ''80%  of  the  infections  among  66,000 
troops  were  due  to  unsanitary  messing  arrangements."  Sub- 
sequent studies  of  over  18,000  hotel  and  restaurant  employees 
showed  that  there  were  85  per  cent  more  eases  among  those 
who  had  eaten  from  hand  washed  dishes  not  disinfected  by 
boiling  water.  This  is  clearly  a  suggestion  for  sanitary  dish 
washing  (immersion  in  boiling  water)  in  the  home  as  well  as 
in  public  eating  places. 

In  discussing  the  administrative  control  of  influenza,  Dr. 
Allen  Freeman  (paper  read  at  the  American  Public  Health 
Association  meeting  in  New  Orleans,  October  28,  1919) 
stresses  the  need  of  further  investigation  into  the  nature  of 
influenza.  He  states  that  although  there  is  every  reason  to 
believe  the  disease  is  caused  by  a  virus  lodging  in  the  nose 
and  mouth  and  spread  from  secretions  of  the  nose  and  mouth 
indirectly  or  through  droplet  infection  these  beliefs  are  not 
proA^ed  by  experiments.  The  paper  holds  that  prompt  iso- 
lation is  important  and  that  educational  measures  are  most 
helpful.  However,  the  prohibition  of  public  gatherings  and 
the  use  of  masks  are  not  to  be  regarded  as  very  important 
means  of  prevention.  Until  we  can  be  certain  that  we  know 
the  virus  of  this  disease,  vaccination  is  not  sound  practice. 
The  procuring  of  adequate  medical  and  nursing  service  and 
the  proper  care  of  pneumonia  cases  are  important  in  reducing 
mortalitv. 


CHAPTER  X 

PUBLIC  HEALTH  ADMINISTRATION 

The  health  of  the  individual  is  protected,  first,  by  proper 
personal  hygiene,  and  second,  by  the  activities  of  organized 
government  in  disease  prevention.  We  are  here  considering 
the  health  administration  of  the  Federal,  State  and  local 
governments. 

Public  Health  Authority. — The  division  of  the  responsibili- 
ties for  administering  public  health  among  National,  State, 
and  Municipal  governments  is  dependent  upon  the  relation- 
ship which  these  bodies  bear  to  each  other  under  the  Consti- 
tution of  the  United  States  and  the  various  State  constitutions. 
Ours  is  a  Federal  government  and  each  State  has  supreme 
power  in  those  questions  which  affect  that  State  alone.  In 
such  matters  it  may,  if  it  chooses,  direct  the  individual  com- 
munity and  it  may  not  be  interfered  with  by  the  Federal 
Government.  In  considering  the  activities  of  the  public 
health  officials  we  shall  first  investigate  their  powers  under 
the  law  and  then  discuss  their  activities. 

FEDERAL  PUBLIC  HEALTH  FUNCTIONS 

The  National  Government  has  only  such  powers  as  are 
granted  to  it  by  the  Constitution.  In  such  matters  State  law 
must  give  way  but  where  power  is  not  specifically  given  to 
the  National  Government  it  is  assumed  that  the  power  lies 
with  the  states.  There  is  no  specific  mention  of  any  power 
over  the  public  health  in  our  Federal  Constitution  but  author- 
ity is  granted  "to  make  all  laws  necessary  and  proper  for 
carrying  into  execution  any  of  the  powers  placed  by  the  Con- 
stitution in  the  Government  of  the  United  States  or  in  any 

ISS 


PUBLIC    HEALTH   ADMINISTRATION'  189 

department  or  officer  thereof."  And  "power  to  regulate  com- 
merce, levy  and  collect  taxes  and  carry  out  treaty  agree- 
ments" are  specifically  granted  to  the  National  Government. 
Certain  public  health  activities  are  very  properly  carried  on 
under  these  broad  powers. 

The  Power  to  Regnlate  Commerce. — The  first  general 
clause  by  which  the  Federal  Government  has  power  to  regu- 
late public  health  is  the  clause  giving  it  power  to  regulate 
commerce  with  foreign  countries  and  among  the  several  states. 
The  words  "commerce"  and  "regulate"  are  not  defined  and 
their  meaning  has  been  gradually  enlarged.  Commerce  is  in- 
terpreted to  include  not  only  the  active  transportation  of 
persons  and  things  from  one  place  to  another  but  also  arti- 
ficial land  and  water  routes,  terminals,  harbors,  vehicles,  and 
the  persons,  both  carriers  and  shippers,  consignees,  employers 
and  employed,  who  are  engaged  in  the  active  transportation. 
Commerce  embraces  purchases  and  sales  and  the  negotiations 
entered  into  in  order  to  lead  to  sales.  Indeed  there  is  a  tend- 
ency to  regard  manufacturing  as  a  part  of  commerce  where 
its  regulation  is  necessary  to  the  effective  regulation  of  what 
is  admittedly  commerce. 

The  power  to  regulate  includes  not  only  the  right  to  charter 
companies  and  the  right  to  regulate  contracts  between  ship- 
pers and  carriers,  carriers  and  their  employees,  between  sellers 
and  purchasers,  but  also  the  right  to  prohibit  commerce  on 
certain  articles,  to  prohibit  certain  methods  of  carrying  on 
commerce  and  to  license  those  engaged  in  commerce. 

The  power  of  the  government  through  this  clause  is  the 
power  to  prohibit,  under  criminal  penalty,  the  interstate  trans- 
portation of  persons  or  articles.  It  includes,  therefore,  the 
power  of  quarantine  against  persons  or  things  to  prevent  their 
entrance  from  one  state  to  another  where  such  an  entry  may 
be  judged  to  endanger  the  public  safety.  In  commerce  with 
foreign  countries  the  government  may  take  action  in  the 
nature  of  either  an  embargo  or  an  inspection. 


190  HYGIENE:     DENTAL   AND    GENERAL 

The  power  of  the  government  to  restrict  the  transportation 
of  an  article  includes  the  power  to  determine  whether  the 
article  transported  falls  within  the  prohibited  class  and  thus 
provision  is  made  requiring  the  labeling  of  articles  and  the 
inspection  at  the  place  of  manufacture  of  articles  intended 
for  interstate  transportation  as  well  as  for  the  licensing  of 
persons  engaged  in  their  manufacture. 

An  important  use  of  this  power  was  the  enactment  of  the 
Food  and  Drug  Law  which  forbids  the  transportation  from 
one  state  to  another  of  adulterated  food  products  and  drugs. 
The  law  was  upheld  by  the  Supreme  Court  as  constitutional. 
On  the  other  hand,  the  Child  Labor  Law  which  forbade  the 
transportation  of  goods  made  in  factories  where  children  un- 
der 14  years  of  age  were  employed,  or  where  there  were  em- 
ployed children  under  16  years  of  age  who  worked  more  than 
eight  hours  a  day  was  not  upheld  by  the  Supreme  Court.  It 
was  declared  unconstitutional  because  it  was  regarded  as  an 
attempt  to  regulate  the  methods  of  manufacture  within  a  state. 
The  transportation  of  articles  manufactured  by  child  labor 
could  not  in  the  nature  of  things  be  harmful  and  therefore  the 
injury  to  health  which  resulted  was  done  in  the  st  ate  of  manu- 
facture and  hence  was  due  to  manufacturing  and  not  to 
commerce. 

Taxation. — The  second  source  of  power  in  regulating  pub- 
lic health  is  the  power  to  "lay  and  collect  taxes,  duties,  im- 
posts, and  excises  to  pay  the  debts  and  provide  for  the  common 
defense  and  general  welfare  of  the  United  States."  The 
power  to  tax  is  in  reality  the  power  to  destroy.  Congress  has 
in  the  taxing  power  a  method  of  protecting  public  health 
which  naturally  lends  itself  to  matters  where  prohibition 
rather  than  regulation  is  sought.  The  only  limit  to  this  power 
is  the  condition  that  the  classification  of  articles  and  persons 
to  be  taxed  must  have  some  reasonable  relation  to  the  object 
sought. 

The  last  revenue  bill  provided  a  prohibitive  tax  on  all  man- 
ufacturers employing  child  labor.     The  litigation  which  is 


PUBLIC    HEALTH   ADMINISTRATION"  191 

bound  to  occur  upon  this  point  will  undoubtedly  determine 
more  definitely  the  limits  of  Federal  power  under  the  right  of 
taxation.  Another  example  of  the  taxing  power  in  the  in- 
terest of  public  health  is  the  Harrison  Act,  which  regulates 
the  use  of  drugs  by  exercising  the  taxing  power. 

Defense  and  Welfare  Powers. — The  power  to  "provide  for 
the  common  defense  and  general  welfare  of  the  United  States" 
is  also  important.  Under  this  power  the  government  has  es- 
tablished a  national  Public  Health  Service  authorized  to  assist 
state  health  authorities  and  cooperate  with  them.  Thus,  al- 
though the  United  States  Government  may  not  interfere  with 
the  sanitary  work  of  the  states  it  may  have  a  far-reaching 
intluence  on  state  health  administration  through  its  power  of 
appropriating  money  for  health  work. 

Treaty  and  War  Powers. — Congress,  no  doubt,  may  exer- 
cise legislative  power  in  carrying  out  the  provisions  of  treaties. 
Such  powers,  in  the  past,  however,  have  not  been  largely  exer- 
cised and  their  limits  are  not  definitely  set.  It  should  also  be 
remembered  that  in  the  District  of  Columbia,  territories  and 
reservations  the  Federal  Government  has  complete  powers,  and 
that  in  time  of  war  its  power  to  raise  and  support  armies  and 
to  provide  a  navy  carries  with  it  the  power  to  do  whatever  is 
necessary  to  protect  the  health  of  soldiers  and  sailors,  even 
within  state  lines. 

The  United  States  Public  Health  Service. — The  most  im- 
portant branch  of  the  Federal  Government  in  its  relation  to 
health  is  the  Public  Health  Service.  The  following  concise 
statement  regarding  its  development  and  organization  was 
supplied  by  the  Chief  of  the  Section  of  Public  Health  Edu- 
cation, Dr.  Charles  Bolduan,  in  a  letter  written  December  6, 
1919: 

The  Public  Health  Service  dates  back  to  the  end  of  the  Eighteenth 
Century  when,  in  1796,  steps  were  taken  for  providing  medical  and 
surgical  relief  to  merchant  seamen.  At  first  tliis  was  financed  by  a 
per  capita  tax  collected  from  the  seamen,  the  funds  being  handled  by 
the  collectors  of  customs  in  the  various  ports.     Subsequently  this  was 


192  HYGIENli:     DENTAL   AND    GENERAL 

changed  into  a  tonnage  tax,  collected  through  the  same  channels.  •  This 
explains  why  the  marine  hospital  work  (the  precedent  of  the  present 
U.  S.  Public  Health  SeTOce)  came  to  be  lodged  in  the  Treasury  De- 
13artment,  for  the  collection  of  customs  was  naturally  a  branch  of 
the  Treasury  Department's  work.  With  the  enormous  growth  of  the 
American  Merchant  Marine  in  the  first  half  of  the  Nineteenth  Century 
this  method  of  providing  for  the  merchant  marine  was  found  to  be 
inadequate  and  the  government,  therefore,  established  "marine  hos- 
pitals"  at  various  important  points. 

In  an  effort  to  guard  against  the  introduction  of  dangerous  pestilen- 
tial diseases  from  without  it  was  natural  that  the  officers  of  the  marine 
hospitals,  stationed  as  they  were  at  the  important  ports  of  entry,  should 
come  into  close  relation  and  take  an  active  interest  in  maritime  quar- 
antine matters.  In  addition  to  this,  the  repeated  introduction  of 
yellow  fever  into  the  southern  states  and  the  alarm  occasioned  thereby 
caused  repeated  calls  to  be  addressed  to  the  Federal  Government  to  take 
charge  of  control  measures  at  the  infected  points  in  order  to  prevent 
the  spread  of  disease  to  other  points  of  the  United  States.  There  be- 
ing no  special  Federal  health  agency,  these  calls  were  naturally  re- 
ferred to  the  United  States  Marine  Hospital  Service.  More  and  more, 
therefore,  this  Service  began  to  undertake  federal  public  health  ac- 
tivities, a  fact  which  was  recognized  by  Congress  when,  in  1902,  it 
changed  the  name  of  the  Service  to  the  United  States  Public  Health  Serv- 
ice and  Marine  Hospital  Service.  More  recently  still,  in  1912,  the  name 
was  still  further  changed  to  its  present  designation,  namely  the  United 
States  Public  Health  Service. 

The  United  States  Public  Health  Service  is  a  bureau  in  the  Treasury 
Department.  At  its  head  is  the  Surgeon-General.  He  is  assisted  by  a 
staff  of  Assistant  Surgeon-Generals.  Most  of  these  have  charge  of  im- 
portant functional  divisions.  As  at  present  organized,  the  work  is 
carried  on  under  the  following  divisions: 

Division  of  Personnel  and  Accoimts.  (As  its  name  implies,  it  has 
to  do  largely  with  matters  of  internal  administration.) 

Bimsion  of  Marine  Hospitals.  (In  addition  to  caring  for  merchant 
seaman,  this  division  has  charge  of  all  the  medical  and  surgical  relief 
work  for  discharged  soldiers,  sailors,  marines  and  nurses  who  are  bene- 
ficiaries under  the  War  Eisk  Insurance  Act.) 

Division  of  Mantime  Quarantine.  (This  conducts  almost  all  the 
maritime  quarantine  stations  for  the  United  States  and  the  insular 
possessions.) 

Division  of  Domestic  Quarantine.  (This  controls  the  important  field 
relating  to  the  control  of  diseases  tJirough  the  interstate  traffic.) 

Division  of  Scientific  Eesearch.     (This  is  a  large  division  engaged 


PUBLIC    HEALTH    ADMINISTRATION  193 

in  studying  tlie  diseases  of  man  through  field  investigations  and  labora- 
tory work.) 

Divisions  of  Sanitary  Reports  and  Statistics.  (This  division  collects 
information  regarding  the  prevalence  of  communicable  diseases,  dis- 
seminates it  through  publications  and  otherwise  to  Health  Officers  and 
Sanitarians  throughout  the  country.) 

Division  of  Venereal  Diseases.  (This  recently  created  division  was 
established  by  Congress  primarily  to  safeguard  the  nation 's  manhood 
against  the   ravages  of   venereal  infection.) 

Section  of  PuMic  Health  Education.  (A  recently  established  activ- 
ity for  promoting  public  health  through  popular  health  education.) 

The  personnel  below  the  rank  of  the  Assistant  Surgeon- 
General  consists  of  Senior  Surgeons  with  a  rating  correspond- 
ing to  that  of  Lieutenant-Colonel  in  the  army,  Passed  Assist- 
ant Surgeons  with  the  rating  of  Captains,  Assistant  Surgeons 
with  the  rating  of  1st  Lieutenants,  Scientific  Assistants  with 
the  rating  of  2nd  Lieutenants,  Pharmacists,  Orderlies,  Tech- 
nicians, and  other  attendants  with  the  rating  of  noncommis- 
sioned officers.  These  grades  are  largely  for  the  convenience 
of  these  Federal  officials  in  order  to  determine  relative  rank 
when  sitting  upon  boards  or  commissions  with  army  and  navy 
officers.  The  Public  Health  Service  is  a  civilian  and  not  a 
military  branch  of  government,  although  during  the  world 
war  it  was  declared  a  branch  of  the  military  service  by  the 
President  of  the  LTnited  States,  being  continued  under  its 
usual  organization. 

The  functions  of  the  Public  Health  Service  have  been  de- 
scribed by  Assistant  Surgeon-General  McLaughlin  as  of  four 
kinds.  Police  duties  are  first  mentioned.  These  include  the 
maintenance  of  quarantine  and  the  prevention  of  the  spread 
of  disease  from  one  state  to  another.  The  second  activity  is 
that  of  investigation.  With  increased  appropriation  from 
Congress  the  Hygienic  Laboratory  of  the  Public  Health  Serv- 
ice at  Washington  should  be  made  a  big  center  of  research  in 
preventive  medicine,  for  it  is  obviously  fitting  that  the  Na- 
tional Government  should  undertake  the  solution  of  the 
nation's  great  disease  problems.     The  third  activitv  is  that 


194  HYGIENE:     DENTAL   AND    GENERAL 

of  demonstration.  With  the  cooperation  of  the  state  and  local 
agencies,  special  pieces  of  work  may  be  undertaken  to  prove 
the  value  of  rural  sanitation  and  other  health  measures.  The 
fourth  activity  is  that  of  the  coordination  of  state  and  local 
activities  in  various  parts  of  the  country  in  order  "to  secure 
a  synchronous  attack  upon  any  disease  with  uniformity  of 
method  over  the  entire  area  of  the  United  States."  For  ex- 
ample in  the  national  campaign  against  venereal  diseases 
Congress  appropriated  one  million  dollars  under  the  Chamber- 
lain-Kahn  bill  and  under  the  cooperating  agency  of  the  Public 
Health  Service  the  various  states  waged  a  uniform  and  suc- 
cessful campaign. 

The  Public  Health  Service  is  the  principal  and  most  im- 
portant health  agency  of  the  Government.  It  has  been  ac- 
credited with  all  the  powers  that  Congress  can  give  it  for 
doing  health  work.  The  nature  of  its  activities  is  limited  by 
the  Constitution  and  the  extent  of  its  activities  is  limited  by 
the  failure  of  Congress  to  give  it  sufficient  appropriations. 
Perhaps  it  is  also  handicapped  by  being  a  semimilitary  organi- 
zation; because  many  people  mistake  the  brown  or  blue  uni- 
forms for  those  of  the  army  or  navy.  The  people  regard 
health  officials  as  "their  servants"  and  object  to  the  "red 
tape"  and  "army  methods"  of  the  Service  which  sometimes, 
perhaps  of  necessity,  lacks  the  personal  consideration  and  tact 
of  local  health  organizations. 

Other  Federal  Health  Agencies. — There  are  two  other  de- 
partments in  the  Federal  Government  which  are  doing  rather 
extensive  health  work,  the  Children's  Bureau  in  the  Depart- 
ment of  Labor  and  the  Bureau  of  Education  in  the  Depart- 
ment of  the  Interior.  Many  of  the  departments  of  the  govern- 
ment are  doing  lesser  amounts  of  health  work  and  much  is 
apparently  being  lost  through  lack  of  centralization  and  co- 
ordination. Attempts  have  already  been  made  to  secure  a 
central  health  administration  and  this  movement  has  doubt- 
less been  strengthened  by  the  recent  organization  of  a  Ministry 
of  Health  in  both  England  and  Canada. 


ruBTJO  HEyvryni  administration  195 

STATE  HEALTH  FUNCTIONS 

Under  our  form  of  government  each  state  bears  the  respon- 
sibility for  its  health  conditions  and  upon  the  state  legislature, 
as  the  supreme  power  of  the  state,  this  responsibility  prima- 
rily rests.  The  Federal  Government  has  no  right  to  interfere 
in  those  matters  which  affect  only  the  state  itself,  but  tlie 
towns  and  municipalities  within  the  state  are  all  bound  to 
enforce  the  state  law.  The  legislators,  limited  only  by  the 
constitution  and  responsible  only  to  the  electorate,  are  su- 
preme in  their  power  .to  determine  what  health  regulations 
shall  be  made  and  what  official  organization  shall  be  provided 
by  each  municipality  and  by  the  state  at  large  to  ad- 
minister public  health.  Since  public  health  administration 
within  the  state  is  directly  dependent  upon  the  law  it  may  be 
profitable  to  consider  the  principles  of  health  legislation  at 
this  point. 

Public  Health  Laws.— Public  health  laws  may  be  divided 
into  two  groups;  those  statutory  laws  creating  the  public 
health  organization,  and  those,  statutory  and  otherwise,  Avhich 
govern  public  health  administration. 

The  first  law  providing  for  health  organization  was  the 
Massachusetts  law  of  1797  establishing  Boards  of  Health  for 
towns  and  giving  each  board  power  to  ''make  such  regula- 
tions as  it  judges  necessary  for  the  public  health  and  safety." 
Since  then  the  other  states  have  made  similar  laws,  the  last 
enactment  being  that  of  Nevada  in  1905,  while  many  of  the 
large  cities  have  had  special  sanitary  provisions  incorporated 
in  their  charters.  The  type  of  local  organization  has  varied 
in  different  states  depending  upon  whether  the  administrative 
unit  of  government  was  the  township  or  the  county.  The 
local  authorities  are  required  to  keep  the  state  authorities  in- 
formed as  to  the  -sanitary  conditions  of  their  districts  and  in 
all  cases  local  health  ordinances  must  not  contravene  the  laws 
of  the  state.  Since  1855  each  state  has  enacted  a  law  creating 
a  State  Board  of  Health  or  its  equivalent. 

In  the  legal  side  of  public  health  administration,  common 


196  HYGIENE  :     DENTAL    AND    GENERAL 

and  constitutional  as  well  as  statutory  laws  are  involved.  The 
common  law,  or  lex  non  scripta,  consists  of  the  court  decisions 
made  in  the  course  of  administering  justice.  The  decision 
of  a  lower  court  or  the  opinion  of  an  attorney  has  little  value 
as  a  precedent,  but  the  decision  of  the  supreme  court  is  bind- 
ing upon  subordinate  courts  until  overruled.  Statutory  laics 
are  enacted  by  legislatures  upon  the  basis  of  common  law  and 
their  official  interpretation  has  the  force  of  additional  legis- 
lation. 

Coincident  with  the  growth  of  common  law  there  is  usually 
the  establishment  of  institutions  such  as  quarantine.  These 
institutions,  however,  may  become  antiquated  and  abandoned 
as  the  quarantine  of  yellow  fever.  When  conflicting  with 
either  statutory  or  constitutional  law  they  are  not  lawful. 

All  authority  for  the  protective  operations  of  government 
including  the  preservation  of  public  health  is  derived  from 
what  is  known  as  police  potver,  an  inherent  function  of  govern- 
ment. In  its  exercise  we  find  cases  where  there  is  sanction 
for  otherwise  illegal  acts,  such,  for  example,  as  the  violation 
of  personal  or  property  rights  to  protect  the  safety  of  the 
people  in  great  epidemics. 

The  use  of  license  is  essentially^  police  in  nature.  A  license 
may  be  issued  with  a  slight  fee  as  in  licensing  milk  dealers 
where  it  is  the  license  rather  than  the  fee  which  serves  to  re- 
strict or  regulate  the  business.  On  the  other  hand,  the  issu- 
ance of  licenses  at  a  prohibitive  cost  has  been  a  reasonable 
use  of  police  power  in  restraining  the  liquor  traffic.  A  tempo- 
rary license,  or  one  which  covers  a  single  act,  is  ordinarily 
called  a  permit. 

AVhere  a  health  officer  is  given  power  of  discretion  he  may 
do  any  act  within  that  discretion,  and  all  that  he  does  will 
be  held  to  have  been  done  with  the  express  authorization  of 
law.  Should  the  health  officer  abuse  his  power  of  discretion 
he  is  amenable  to  prosecution,  but  the  act  to  be  criminal  must 
be  wilful  and  corrupt,  and  proof  of  this  rests  upon  the  com- 
plainant.    If  the  officer  has  deviated  from  his  legal  authority 


PUBLIC    HEALTH    ADMINISTRATION  197 

through  a  mistake  in  interpreting  his  power  or  a  mistake  of 
fact  in  applying  the  law  he  is  liable  as  a  private  wrongdoer 
and  responsible  in  such  damages  as  may  be  proved. 

An  officer  is  not  subject  to  a  private  action  for  neglect  of 
an  exclusively  public  duty  even  to  a  person  specially  injured 
thereby,  and  in  some  cases  even  though  the  act  were  unlawful 
and  malicious.  If  discretion  be  left  entirely  to  the  admini- 
strative officer,  there  is  no  way  in  which  he  can  be  forced  to 
act.  In  the  enforcement  of  statutory  law,  an  officer  is  sub- 
ject to  mandamus  and  also  to  probate  action  whenever  ho 
shall  deviate  from  his  prescribed  limits  of  duty. 

Some  laws  like  quarantine  are  mandatory  as  to  action,  but 
discretionary  as  to  method.  In  court  proceedings  if  the  law 
be  specific  the  only  questions  which  may  arise  are  those  of 
fact;  if  discretionary,  questions  of  fact,  reasonableness  and 
extent  of  discretion  may  be  presented. 

A  city's  administration  depends  upon  fixed  rules.  They 
are  either  written  regulations  or  unwritten  usages.  "When  a 
penalty  is  attached  to  a  violation  of  the  rules  or  regulations  of 
the  board  of  health,  such  rules  must  be  published  and  due 
notice  given  before  they  can  be  made  effective.  Violations  of 
the  regulations  may  be  punished  by  indictment,  action  being 
uniformly  brought  in  the  name  of  the  town  or  city. 

Injunction  is  applicable  to  prevent  executive  action,  the 
taking  or  impairment  of  property  or  the  creation  of  nuisances. 
It  is  not  used  to  direct  or  restrain  the  exercise  of  discretion- 
ary authority. 

A  public  health  nuisance  is  a  state  of  affairs  which  is  dan- 
gerous to  public  health.  Obviously  a  thing  may  be  a  nuisance 
under  either  common  or  statutory  law.  In  a  case  of  exigency 
the  health  authorities  may  summarily  abate  the  nuisance,  but 
if  the  owner  of  the  property  cannot  get  a  formal  trial  before 
the  abatement  he  is  entitled  to  a  hearing  afterward.  The 
burden  is  then  upon  the  authorities  to  justify  their  action.* 


*For  an  extensive  discussion  of  public  lieahli  legislation  see  ['.  S.  Public  Health 
Bulletin  No.  64  published  in  August,  1912,  "Organisation.  Poivcrs  and  Duties  of 
Health  .4uthorities" ;  also  "Legal  Principles  of  Public  Health  .-Idniinistration,  by 
Henry    1>.  Ilenienwav. 


198 


HYGIENE:     DENTAL   AND   GENERAL 


State  Health  Administration ;  Organization. — Turning  now 
to  a  consideration  of  state  health  administration  we  find  that 
the  oldest  type  of  organization  placed  the  administration  of 
public  health  in  the  hands  of  a  Secretary  of  the  State  Board 
of  Health.  He  was  the  executive  officer  and  his  activities 
were  guided  by  the  policy  and  wishes  of  the  Board.  Recently 
many  states  have  changed  their  type  of  organization  from  a 
State  Board  of  Health  to  a  State  Department  of  Health  under 
the  direction  of  a  Commissioner  with  an  Advisory  Council. 
New  York  initiated  this  movement  with  its  law  of  1912,  Mass- 
achusetts soon  followed  suit  with  a  similar  law,  containing  a 
few  modifications  and  since  then  Maine,  New  Jersey,  Connecti- 
cut, California,  Ohio  and  several  other  states  have  adopted 
some  form  of  the  New  York-Massachusetts  plan. 

The  organization  of  the  State  Department  of  Public  Health, 
of  Massachusetts,  July  1,  1920,  is  as  follows : 

Working  under  the  advice  of  the  Public  Health  Council  is 
the  Commissioner  of  Health  whose  organization  is  made  up 
01  the  following  divisions : 


1.  Sanitary  Engineering 

Director  and  Chief  Engr 1 

Asst.  Engineers    12 

Draftsman  1 

Clerical .5 

Messenger    1 


J  cUviUcs 

Advice  tu  cities  and  towns  in 
regard  to  water  and  sewage 
problems. 

Field  surveys  and  investiga- 
tions necessitated  thereby. 
Special  Engineering  projects 
imposed  by  the  General  Court. 


2.  Water  and  Sewage 

Laboratories 

Director  and  Clif .  Chemist ...  1 

Asst.   Chemists   5 

Biologist 1 

Laboratory  Asst 1 

Clerical 2 

Lawrence  Expt.  Sta. 

Asst.  Chemist   1 

Bacteriologist    1 

Laboratory  Asst I 

Filter  Attendant   1 

Laborer    1 

Activities 
Investigation   of  water,   sew- 
age and  trade  waste  x^roblems. 


PUBLIC    HEALTH   ADMINISTRATION 


199 


3.  Food  and  Drugs 

Director  and  Analyst   1 

Assistant  Analysts -t 

Food  and  Drug  Inspectors.  .  .  A 

Veterinary  Inspectors 3 

Cold  Storage  Inspectors 2 

Clerical  Inspectors 3 

Messenger    1 

Activities 
Examination    of    milk,    food 
and  drugs.     Dairy  Inspection. 
Cold  Storage  Inspection. 
Slaughtering  Inspection. 
Food  Economics. 
Drug  Addictions. 
Patent  Medicine  Frauds. 
Arsphenamine  Production. 


4.  Administration 

Clerical 6 

Messengers     2 


Activities 
Correspondence. 
Financial. 
Statistical. 
Eecords. 


5.  Communicable  Diseases 

Director    1 

Epidemiologist    1 

Dist.  Health  Ofacers 8 

Bacteriologist    1 

Asst.  Bacteriologist 2 

Laboratory  Asst 2 

Clerical 6 

Sub-division    of    Venereal 
Diseases 

Chief 1 

Epidemiologists    2 

Clerical 4 

Inspector    1 

Educationalist     1 

Subsidized  Clinics   1  fi 

Activities 
Prevention    of   all   Communi- 
cable Diseases,  except  tubercu- 
losis. 


6.  Hygiene 

Director    1 

Asst.  to  Director 1 

Health   Instructor    1 

Field  Supervisor 1 

Clerical 2 

Dental  Hygienist   1 

Instructor  in  Foods 1 

Sub-division  of 
Public  Health  Nursing 

Chief    1 

Nurses    3 


Activities 
Infant  Mortality: 
Child   Hygiene. 
Industrial  Hygiene. 
Eural  Hygiene. 
Health  Instruction. 


200  HYGIENE:  DENTAL  AND  GENERAL 

7.  Biologic  Laboratofjes  8.  Tuberculosis     (Sanatoria) 

*Director    1  Director    1 

Asst.  Directors 2  Clerical     4 

Expert  Asst 1  Visitor    .1 

Laboratory  Assts 5  Superintendents    4 

Other  Assts 3  Hospital  Staffs ?? 

Technician   1 

Clerical     1 

Janitor   1 

A ctivities 

Manufacture  and  Distribu- 
tion of  Diphtheria  Antitoxin, 
Smallpox  and  Typhoid  vaccines. 

Antimeningitis     serum.       Was-  Activities 

sermann  tests  for  Syphilis.  Prevention     of     Tuberculosis 

*Part  time.  and  Treatment  in  Sanatoria. 

The  work  to  be  done  is  practically  the  same  no  matter  what 
the  type  of  organization  although  naturally  the  extensiveness 
of  the  work  done  by  each  state  varies  with  the  size  of  its 
health  appropriation,  the  efficiency  and  number  of  its  person- 
nel and  the  extent  to  which  the  state  supervises  local  health 
administration.  We  shall  use  the  new  type  of  organization 
in  describing  state  health  activities,  because  it  is  already  be- 
coming the  common  type  of  organization  and  because  it  lends 
itself  well  to  a  description  of  health  functions. 

The  essential  features  of  the  New  York  State  Department 
of  Health  are  set  forth  in  the  law  which  created  it.  There 
are  provisions  for  a  Commissioner,  a  Public  Health  Council,  a 
Sanitary  Code,  the  employment  of  District  Health  Officers, 
and  the  creation  of  various  Divisions. 

The  Commissioner  is  appointed  for  a  term  of  six  years  and 
must  have  had  ten  years  experience  in  the  practice  of  his 
profession  and  in  public  health  duties.  The  Deputy  Com- 
missioner is  appointed  and  at  pleasure  removed  by  him.  The 
duties  of  the  Commissioner  include  a  general  supervision  of 
the  health  activities  of  the  State,  the  enforcement  of  public 
health  laws  and  the  sanitary  code,  the  study  of  health  con- 


PUBLIC    HEALTH    ADMINISTRATION  201 

ditions,  and  the  keeping  of  vital  statistics,  while  his  powers 
include  the  right  to  modify  a  local  ordinance  and  the  right  of 
entry  which  he  may  delegate  to  any  of  his  employees. 

The  Public  Health  Council,  is  composed  of  the  Commissioner 
and  six  other  members,  three  of  whom  are  physicians,  ap- 
pointed by  the  Governor  for  a  term  of  six  years  and  receiving 
a  salary  of  $1000.00  per  year  over  and  above  necessary  travel- 
ling expenses.  The  Council  has  no  executive  or  administra- 
tive duties  but  acts  in  an  advisory  capacity  to  the  Commis- 
sioner and  may  at  any  time  offer  suggestions. 

The  Sanitary  Code,  consisting  of  rules  and  regulations  af- 
fecting the  security  of  life  or  health,  is  enacted  by  the  Public 
Health  Council.  The  provisions  of  this  Sanitary  Code  have 
the  force  and  effect  of  law  in  all  parts  of  the  State  and  are 
only  restricted  in  that  they  shall  not  discriminate  against 
any  licensed  physician.  These  regulations  are  filed  with  the 
Secretary  of  State.  In  enforcement  they  supersede  any  local 
ordinances  which  may  be  inconsistent  with  them,  and  include 
besides  sanitaiy  regulations  a  statement  of  qualifications  for 
Directors  of  Divisions,  Sanitary  Supervisors,  Local  Health 
Officers,  and  Public  Health  Nurses. 

It  is  to  be  noted  that  the  legislature  has  delegated  a  limited 
amount  of  "law-making  power"  to  the  Public  Health  Council. 
In  sucli  a  case  the  delegation  of  power  is  judicious  and  pro- 
gressive, for  only  a  body  of  experts  is  qualified  to  work  out 
the  details  of  public  health  regulations. 

It  is  definitely  provided  that  there  shall  be  in  the  Depart- 
ment of  Health  nine  Divisions,  namely : 

1.  Division  of  Administration. 

2.  Division  of  Sanitary  Engineering. 

3.  Division  of  Laboratories  and  Research. 

4.  Division  of  Communicable  Diseases. 

5.  Division  of  Vital  Statistics. 

6.  Division  of  Publicity  and  Education. 

7.  Division  of  Child  Hvgiene. 


202  HYGIENE:     DENTAL   AND   GENERAL 

8.  Division  of  Public  Health  Nursing. 

9.  Division  of  Tuberculosis. 

A  division  of  Venereal  Diseases  has  since  been  added. 

Sanitary  Districts  are  formed  by  the  Health  Commissioner, 
and  District  Health  Officers  are  appointed  by  him.  It  is  their 
duty  to  keep  in  touch  with  local  health  officers,  aiding  them 
when  necessary,  to  make  special  surveys,  hold  conferences,  ad- 
just local  questions  of  dispute,  study  mortality,  promote  the 
registration  of  births,  inspect  camps  and  Indian  reservations, 
enlist  physicians  for  emergency  service,  and  assist  in  public 
education,  and  the  enforcement  of  the  sanitary  code. 

Administrative  Functions. — Let  us  consider  briefly  the 
activities  of  the  various  divisions  of  the  State  Department  of 
Health. 

One  of  the  first  recognized  duties  of  the  state  has  been  the 
collection  of  vital  statistics.  This  includes  the  recording  and 
analyzing  of  data  concerning  deaths,  births,  marriages,  popu- 
lation, and  diseases.  The  keeping  of  vital  statistics  is  the 
bookkeeping  of  a  state  by  which  it  keeps  a  record  of  changes 
in  the  population,  which  represents  its  great  item  of  wealth. 
Just  as  an  industrial  concern  keeps  an  account  of  its  material 
assets  and  liabilities  so  the  state  must  keep  a  record  of  its 
human  assets  and  liabilities.  It  must  know  whether  it  is 
gaining  or  losing  and  where  and  how.  If  disease  is  to  be  pre- 
vented and  lives  are  to  be  saved  careful  records  must  be  kept 
to  show  where,  when  and  how  diseases  and  deaths  are  oc- 
curring. 

The  recording  and  interpretation  of  vital  statistics  is  a 
science  in  itself  and  highly  trained  vital  statisticians  are  em- 
ployed for  this  work.  The  layman  may  not  be  particularly 
interested  in  the  methods  of  interpreting  statistics  but  he  will 
at  least  wish  to  know  what  is  meant  by  the  most  commonly 
computed  rates. 

The  hirtJi  rate  is  the  number  of  births  annually  per  thou- 
sand population.     The  crude  death  rate  is  the  number  of 


PUBLIC   HEALTH   ADMINISTRATION  203 

deaths  annually  per  thousand  population.  We  also  have  what 
are  termed  specific  death  rates  which  state  the  number  of 
deaths  per  thousand  or  per  100,000  population  for  specific 
diseases.  For  example  a  low  typhoid  death  rate  is  4.3  per 
100,000. 

Another  important  figure  is  the  morhidity  rate  which  is 
the  number  of  cases  of  specific  disease  per  thousand  popula- 
tion (sometimes  expressed  as  the  number  per  100,000  popu- 
lation). The  fatality  rate  is  the  number  of  deaths  from  a 
specific  disease  per  100  cases  (the  per  cent  fatality).  We 
say,  for  example,  that  among  pneumonia  cases  the  fatality 
rate  was  33. 

By  such  figures  our  "life  and  death  bookkeeping"  shows 
us  how  we  can  tell  just  where  our  various  communities  stand 
in  the  matter  of  life-saving  and  health.  When  we  realize  that 
such  figures  show  whether  we  live  in  a  safe  and  healthy  com- 
munity or  a  dangerous  and  sickly  one,  the  statistics  of  our 
state  and  local  health  officers  become  most  interesting  reading. 
The  registration  of  births,  marriages  and  deaths  is  also  im- 
portant for  legal,  social  and  j^roperty  rights. 

The  Division  of  Administration,  which  is  presided  over  by 
the  Health  Commissioner,  includes  a  supervision  over  the 
work  of  the  district  health  officers,  accounts,  salaries,  expendi- 
tures and  other  administrative  details. 

An  increasingly  important  division  is  that  of  Public  Health 
Education.  It  embraces  the  publicity  work  of  the  State  De- 
partment of  Health,  such  as  the  circulation  of  the  reports 
issued  by  the  department,  publicity  work  through  the  news- 
papers, the  showing  of  health  exhibits  in  various  parts  of  the 
state,  the  issuing  of  pamphlets  and  instructive  material  to 
school  children  and  to  people  generally,  lectures,  moving 
pictures  and  all  of  the  numerous  and  valuable  activities  by 
Avhich  the  state  health  department  places  before  the  people  the 
important  principles  concerning  the  care  of  the  health. 

The  functions  of  the  Division  of  Sanitary  Engineering  are 
to  safeguard  the  water  supplies  and  to  insure  proper  waste 


204  HYGIENE:     DENTAL   AND    GENERAL 

disposal  throughout  the  state.  Such  a  department  maintains 
facilities  for  water  and  sewage  analysis  and  is  able  to  furnish 
the  advice  of  an  expert  Sanitary  Engineer  in  any  problem  of 
water  supply  and  waste  disposal.  These  problems  will  be  con- 
sidered in  a  special  chapter. 

The  special  duties  of  the  Division  of  Communicable  Diseases. 
include  activities  in  controlling  and  limiting  the  spread  of 
various  communicable  diseases.  An  epidemiologist  is  usually 
attached  to  the  Department,  who  promptly  investigates  in- 
cipient epidemics  enabling  the  division  to  take  more  prompt 
and  intelligent  steps  in  restricting  the  disease. 

The  Division  of  Child  Hygieyie  maintains  a  personnel  of 
trained  workers  in  subjects  of  infant  and  child  welfare,  who 
make  surveys,  develop  special  state  and  local  campaigns  to 
improve  the  hygienic  conditions  of  maternity,  infancy  and 
childhood  and  cooperate  with  private  child-health  agencies 
througli  the  state. 

The  Division  of  PiCblic  Healtli  Nursing  determines  the 
qualifications  of  the  public  health  nurse,  employs  a  corps  of 
nurses  to  assist  district  health  officers  and  broadens  the  useful- 
ness of  such  nurses  as  are  employed  by  various  communities 
in  the  state  through  its  assistance  and  cooperation. 

The  Division  of  Laboratories  and  Researcli  provides  free 
laboratory  diagnosis  of  communicable  diseases,  prepares  and 
distributes  vaccines  and  antitoxins  to  the  medical  profession 
and  carries  on  public  health  research. 

The  Division  of  Tuberculosis  directs  the  operation  of  State 
Tuberculosis  Hospitals  and  Sanatoria,  and  assists  local 
communities  to  combat  the  disease  by  investigating  conditions 
and  showing  the  value  of  early  reporting,  dispensary  service, 
milk  control  and  other  measures. 

Nearly  all  of  the  states  have  recently  established  a  Division 
of  Venereal  Diseases  as  a  result  of  the  campaign  waged  by  the 
Federal  Government  subsequent  to  the  passage  of  the  Cham- 
berlain-Kahn  Act  which  offers  temporary  financial  assistance 
to   states   in  the   controlling   of  venereal   diseases   provided 


PUBLIC    HEALTH    ADMINISTRATION  205 

proper  regulations  and  a  suitable  organization  are  established. 
The  organization  of  a  state  health  department  is  more  or 
less  elastic  and  not  all  of  these  divisions  are  present  in  every 
state.  New  divisions  may  be  established  and  old  divisions 
may  be  abolished  to  fit  the  need  of  the  occasion. 

LOCAL  HEALTH  ADMINISTRATION 

Authority. — Before  discussing  local  health  administration 
it  may  be  well  to  say  something  about  the  division  of  authority 
between  the  state  and  local  governments  since  their  relation- 
ships are  widely  varying.  In  Pennsylvania  for  example  there 
is  a  centralized  system.  The  local  organization  is  under  the 
control  of  the  state  organization.  In  Massachusetts  the  Legis- 
lature has  given  to  the  state  organization  only  the  power  to 
advi\se  and  investigate  with  no  direct  control  over  the  local 
health  authorities.  In  every  state  the  supreme  authority  is 
the  state  legislature  and  it  can  do  as  it  sees  fit  in  giving  power 
to  the  state  organization. 

There  are  dangers  in  either  of  the  extremes  mentioned.  If 
the  State  Department  of  Health  has  power  over  every  local 
health  officer  it  must  accept  the  responsibility  for  his  activi- 
ties and  the  townspeople  have  an  opportunity  to  blame  the 
state  department  if  anything  goes  wrong.  On  the  other  hand, 
if  the  State  has  no  power  over  local  health  officials,  dangerous 
conditions  may  remain  uncorrected  because  of  inefficient  and 
careless  local  administration.  We  are  perhaps  tending  to- 
ward the  more  centralized  system  in  the  country  as  a  whole 
but  it  would  seem  that  the  system  Avhich  allows  the  state  de- 
partment limited  but  not  complete  control  over  local  author- 
ities or  additional  power  in  emergencies  is  preferable  to  either 
extreme.  In  some  states,  legislation  is  being  enacted  giving 
the  state  department  power  to  administer  health  in  any  com- 
munity when  the  welfare  of  other  communities  in  the  state 
may  be  endangered  or  injuriously  affected.  For  example,  if 
the  quarantine  measures  of  a  town  are  insufficient  the  state 


206  HYGIENE:     DENTAL   AND    GENERAL 

may  step  in  and  make  its  regulations  more  strict.  This  sort  of 
law  leaves  the  responsibility  for  community  health  with  the  lo- 
cal or  municipal  officials  but  gives  the  state  power  to  protect 
the  health  of  the  whole  state  whenever  it  may  be  endangered 
by  local  inefficiency. 

Local  Health  Org-anization. — In  any  case  the  major  duty 
of  enforcing  public  health  law  and  maintaining  healthful  con- 
ditions is  with  the  town  or  the  city.  Throughout  the  country 
there  is  a  fairly  uniform  local  health  organization  which  con- 
sists of  a  Board  of  Health  with  a  Health  Officer  or  an  Execu- 
tive Secretary.  Upon  the  Health  Officer  there  rests  the  re- 
sponsibility of  administering  health  and  upon  the  Board  of 
Health  there  rests  the  responsibility  of  directing  health  activ- 
ities. The  above  discussion  of  public  health  laws  describes 
the  health  officer's  responsibility  and  his  powers  of  discretion 
regarding  them. 

There  is  a  tendency  in  some  places  to  place  responsibility 
upon  the  local  health  officer  instead  of  leaving  it  with  the 
board  of  health.  In  some  states  the  health  officer  may  be 
appointed  to  replace  the  board  of  health  and  in  Massachusetts 
there  has  recently  been  legislation  allowing  Local  Health  De- 
partments to  be  formed — a  type  of  organization  similar  to  that 
of  the  state.  Here  a  local  Health  Commissioner  is  appointed 
with  an  advisory  committee.  This  sets  the  responsibility  up- 
on the  health  officer  but  gives  him  the  benefit  of  advice  and 
support  from  a  committee  or  council. 

The  activities  of  a  local  health  department  are  many  and 
varied.  It  is  its  duty  to  enforce  all  of  the  state  laws  regard- 
ing health  and  disease,  and  to  enforce  in  addition  such  ordi- 
nances or  local  regulations  as  may  be  in  effect  and  related  to 
public  health. 

An  important  duty  of  the  local  department  is  the  main- 
tenance of  a  puMic  health  laboratory  where  laboratory  diag- 
noses for  infectious  diseases  may  be  made  and  where  exami- 
nations of  the  water,  milk,  butter,  vinegar  and  foods  are  car- 
ried out.     Laboratories  in  small  communities  usually  begin 


PUBLIC    HEALTH    ADMINISTRATION  207 

with  the  examination  of  water  and  milk,  and  then  add  diag- 
noses for  diphtlieria,  tuberculosis,  septic  sore  throat,  syphilis 
and  other  infectious  diseases.  In  addition  such  a  laboratory 
often  makes  tests  for  the  purchasing  department  of  the  city, 
analyzing  flour,  coal  and  other  substances. 

Other  activities  include  the  isolation  and  quarantine  of  in- 
fectious diseases,  subsequent  disinfection  where  necessary,  the 
abatement  of  nuisances,  the  supervision  of  hotels  and  restau- 
rants, a  supervision  over  sewage  and  garbage  disposal,  the  su- 
pervision over  housing  conditions,  and  the  administration  of 
special  activities  such  as  public  health  nursing,  infant  welfare, 
city  hospitals,  the  control  of  epidemics,  the  collection  of  vital 
statistics,  the  making  of  regular  reports  to  state  department 
of  health,  and  many  other  matters.  The  problems  of  water 
and  food  supplies,  milk  control,  and  waste  disposal  will  be 
considered  in  special  chapters  as  will  the  subject  of  school 
hygiene. 

The  Health  Officer. — From  such  a  list  of  activities  it  is 
obvious  that  public  health  administration  involves  a  variety  of 
tasks.  The  local  health  officer  must  know  the  fundamentals 
of  sanitary  engineering  or  sanitation  and  the  important  facts 
of  hygiene.  By  training  the  sanitary  engineer  or  the  physi- 
cian is  best  adapted  for  this  type  of  work,  but  either  should 
have  a  supplementary  training.  Public  health  administration 
is  a  distinct  calling  demanding  a  knowledge  of  a  different 
group  of  subjects  than  go  to  make  up  any  other  profession. 
In  this  country  we  are  rapidly  learning  that  the  public  health 
officer  must  be  a  specially  trained  man  and  the  number  of  men 
with  special  training  in  public  health  is  rapidly  increasing. 

Unofficial  Health  Activities. — There  are  many  national 
health  organizations  in  the  United  States  and  many  local 
health  societies  interested  in  specific  or  general  health  prob- 
lems. It  seems  reasonable  that  the  function  of  these  private 
health  organizations — and  it  is  a  useful  function — is  to  develop 
those  phases  of  health  activities  which  the  health  department 
of  a  community  is  not  yet  ready  to  handle  or  which  it  cannot 


208  HYGIENE  :     DENTAL    AND   GENERAL 

well  handle  because  of  the  particular  problem  involved.  For 
example,  cancer  research  cannot  be  carried  out  by  the  individ- 
ual community,  it  might  be  done  by  the  U.  S.  Public  Health 
Service  but  excellent  work  may  be  done  by  a  society  specifi- 
cally interested  in  the  problem.  Activities  like  the  prevention 
of  tuberculosis,  which  would  reasonably  fall  under  the  work 
of  the  organized  health  authorities,  should  be  cared  for  by 
private  organizations  to  that  extent  to  which  the  local  com- 
munity is  not  able  to  handle  the  problem. 

The  society  of  professional  public  health  workers  is  the 
American  Public  Health  Association.  It  includes  not  only 
the  majority  of  people  professionally  engaged  in  public  health 
but  an  increasingly  large  number  of  people  with  special  pub- 
lic health  interests.  Its  official  organ  is  the  American  Journal 
of  Public  Health. 

Other  societies  and  health  organizations  of  national  impor- 
tance include:  The  American  Red  Cross,  Department  of 
Health  Service,  Washington,  D.  C. ;  The  American  Association 
of  Industrial  Physicians  and  Surgeons,  Harrisburg,  Pa. ;  The 
American  School  Hygiene  Association,  Albany,  N.  Y. ;  The 
American  Social  Hygiene  Association,  105  West  40th  St., 
New  York  City;  The  American  Society  for  the  Control  of 
Cancer,  New  York  City ;  The  Child  Health  Organization,  New 
York  City ;  The  International  Health  Commission,  New  York 
City;  The  Life  Extension  Institute,  New  York  City;  The  Na- 
tional Child  Welfare  Association,  New  York  City;  The  Na- 
tional Committee  for  the  Prevention  of  Blindness,  New  York 
City;  The  National  Committee  for  Mental  Hygiene,  New  York 
City;  The  National  Committee  on  Malaria,  Birmingham,  Ala- 
bama ;  The  National  Organization  for  Public  Health  Nursing, 
New  York  City;  The  National  Tuberculosis  Association,  Bal- 
timore, Md. ;  and  The  Russell  Sage  Foundation,  Battle  Creek, 
Michigan. 


CHAPTER  XI 

FOOD  CONTROL 

Thus  far  we  have  considered  food  from  the  standpoint  of 
diet.  Under  food  control  we  shall  consider  the  adulteration 
and  sanitation  of  foods. 

FOOD  ADULTERATION 

Cost  of  Adulteration. — It  might  be  said  that  the  prevention 
of  food  adulteration  is  more  for  the  purpose  of  protecting  the 
poeketbook  than  for  protecting  the  health.  The  fraud  prac- 
ticed in  food  adulteration  may  sometimes  he  harmless  but,  if 
the  adulteration  reduces  the  nutritive  quality  of  a  food  and 
adds  some  poisonous  or  infected  substance  the  culprit  who 
practices  food  adulteration  not  only  robs  the  consumer  but  at- 
tacks his  health. 

Some  people  have  the  mistaken  impression  that  almost  all 
food  is  adulterated.  Although  the  amount  of  adulteration 
varies  in  different  states  according  to  the  nature  of  the  Pure 
Food  Law  and  the  efficiency  of  law  enforcement,  still  the  foods 
which  are  adulterated  are  greatly  in  the  minority.  Consider- 
ing the  country  at  large  it  has  been  estimated  that  15  per  cent 
of  the  food  consumed  is  adulterated.  If  this  is  true,  based 
on  an  estimate  of  a  $3.00  weekly  expenditure  per  capita,  the 
people  of  the  United  States  are  paying  about  two  and  a  half 
billion  dollars  a  year  for  adulterated,  low  grade  or  inferior 
food.  If  we  accept  the  figures  of  experts  who  estimate  that 
2  per  cent  of  adulterated  food  is  injurious  to  health  we  find 
that  the  American  people  are  paying  yearly  over  $46,000,000 
for  food  which  actually  brings  them  definite  physical  injury. 
Comparing  present  conditions  with  expert  studies  made  sev- 
eral years  ago  it  appears  that  Massachusetts  saves  over  a  mil- 

209 


210  HYGIENE:     DENTAL   AND    GENERAL 

lion  dollars  for  the  public  annually  by  the  enforcement  of  the 
Pure  Food  Law. 

Nature  and  Cause  of  Adulteration.— Pood  adulteration 
has  now  become  a  highly  specialized  art.  Mixing  sand  with 
sugar  and  making  milk  out  of  chalk  are  not  practiced  because 
the  detection  of  such  simple  fraud  is  too  easy.  The  man  who 
adulterates  food  now  employs  the  skill  of  the  chemist  and  an 
ingenuity  equal  to  that  of  the  theater  "make-up  man"  in 
preparing  his  products.  Coffee  has  been  found  which  con- 
sisted of  molasses  and  flour  molded  into  the  shape  of  coffee 
berries.  American  cotton-seed  and  peanut  oil  from  the  south- 
ern states  have  been  sent  abroad  and  refined  then  returned  to 
us  as  pure  Mediterranean  Olive  Oil,  It  is  only  by  combating 
the  craft  of  the  manufacturer  with  the  skill  of  the  trained 
analyst  that  this  type  of  food  adulteration  can  be  detected. 

Keen  competition  and  the  desire  for  greater  profits  are  im- 
portant in  causing  food  adulteration.  People  demand  goods 
out  of  season  and  foods  from  distant  parts  of  the  world  at 
cheap  prices.  The  American  wants  goods  done  up  in  fancy 
packages,  stamped  with  foreign  labels,  and  served  in  an  ex- 
travagant fashion.  It  is  no  wonder  that  many  food  manu- 
facturers have  discovered  with  Barnum  that  "the  public  likes 
to  be  humbugged." 

Pure  Food  Laws. — ^It  is  not  the  purpose  of  a  Pure  Food 
Law  to  prohibit  the  making  of  cheap  foods  or  even  of  second 
quality  foods,  but  it  does  insist  that  these  foods  shall  be  sold 
for  what  they  really  are  and  not  passed  off  upon  the  public 
for  first  quality  materials.  It  is  good  to  have  secdnd  quality 
foods  in  the  market  if  they  are  clean  and  wholesome  because 
they  are  inexpensive.  For  example,  catsup  which  is  made 
largely  from  tomato  skins,  may  be  nearly  as  good  as  that 
made  from  the  fleshy  part  or  inside  of  the  tomato,  provided 
that  the  material  is  properly  washed  and  sterilized;  for  the 
difference  in  food  value  in  a  condiment  is  not  important. 
What  we  wish  to  prevent  is  the  use  of  dirty  tomato  skins  pre- 
pared in  an  unsanitary  manner  or  the  sale  of  second  grade 


FOOD    CONTKOTj  211 

catsup  under  misleading  labels.     The  public  is  entitled  to 
know  what  it  is  buying. 

According  to  the  Federal  Pure  Food  and  Drug  Act  which 
was  passed  in  1906  a  substance  is  considered  adulterated : 

(1)  If  a  substance  has  been  mixed  with  it  to  reduce  the 
qualit}'  or  strength.  (Cocoa  shells  mixed  with  cocoa  or  choc- 
olate, or  watered  milk.) 

(2)  If  any  substance  has  been  substituted  wholly  or  in 
part.  (Cottonseed  oil  for  olive  oil,  cane  sugar  for  maple 
sugar. ) 

(3)  If  a  valuable  constituent  has  been  wholly  or  partly 
abstracted.     (Skimmed  milk.) 

(4)  If  it  is  mixed,  colored,  powdered,  coated  or  stained  in 
any  manner  whereby  inferiority  is  concealed.  (Lemon  ex- 
tract colored  with  a  yelloAV  dye,  bleached  flour.) 

(5)  If  it  contains  any  added  poisonous  or  any  other  added 
ingredient  deleterious  to  health.  (Formaldehyde,  arsenic, 
lead,  salicylic  acid,  boric  acid  or  benzoates.) 

(6)  If  it  consists  in  whole  or  in  part  of  a  filthy,  decom- 
posed or  putrid  animal  or  vegetable  substance,  or  any  portion 
of  an  animal  unfit  for  food  or  if  it  is  the  product  of  a  diseased 
animal,  or  one  that  has  died  otherwise  than  by  slaughter. 
(Oysters  contaminated  with  sewage,  Avormy  figs,  embalmed 
beef,  etc.)  [Under  this  clause  reasonable  sanitary  require- 
ments can  be  enforced.] 

The  reason  certain  foods  continue  to  be  adulterated  in  spite 
of  this  law  is  because  the  adulteration  is  so  difficult  to  detect. 
For  example,  the  sugar  of  the  maple  is  identical  chemically 
with  cane  sugar  and  it  has  been  impossible  to  detect  the  fraud. 
The  result  is  that  more  Vermont  maple  sugar  is  made  outside 
the  state  than  all  the  trees  in  Vermont  could  produce.  New 
"Vermont  maple  sugar"  appears  in  tlie  market  long  before 
the  sap  starts  in  tlie  maple  groves  of  New  England.  A  Con- 
gressional Committee  was  once  told  of  the  experience  of  a 
Chicago  firm  which  had  sent  to  the  trade  150  barrels  of  pure 
maple  syrup.     Of  this  147  barrels  were  returned  with  the 


212  HYGIENE:     DENTAL   AND   GENERAL 

complaint  that  it  was  too  strong.  Mixed  with  cane  syrup 
this  same  lot  was  again  sent  ont  and  only  praise  was  had  from 
the  buyers. 

Misbranding. — The  Food  and  Drugs  Act  requires  that  no 
drug  or  article  of  food  shall  be  falsely  labelled  as  to  its  con- 
tents or  as  to  the  state  or  country  in  which  it  is  manufactured 
or  produced.     A  food  is  deemed  to  be  misbranded : 

(1)  If  it  be  an  imitation  of  or  offered  for  sale  under  the  distinctive 
name  of  another  article. 

(2)  If  it  be  labeled  or  branded  so  as  to  deceive'  or  mislead  the  iDur- 
ehaser,  or  purport  to  be  a  foreign  product  vrhen  not  so,  or  if  the  con- 
tents of  the  package  as  originally  put  up  shall  have  been  removed,  in 
whole  or  in  part,  and  other  contents  shall  have  been  placed  in  such 
package,  or  if  it  fail  to  bear  a  statement  on  the  label  of  the  quantity 
or  proportion  of  any  morphine,  opium,  cocaine,  heroin,  alpha  or  beta 
eucaine,  chloroform,  cannabis  indica,  chloral  hydrate,  or  acetanilide, 
or  any  derivative  or  preparation  of  any  such  substances  contained 
therein. 

(3)  If  in  package  form,  and  the  contents  are  stated  in  terms  of 
vreight  or  measure,  they  are  not  plainly  and  correctly  stated  on  the 
outside  of  the  package. 

(4)  If  the  package  containing  it  or  its  label  shall  bear  any  state- 
m-ent,  design  or  device  regarding  the  ingredients  or  the  substances 
contained  therein,  which  statement,  design  or  device  shall  be  false  or 
misleading  in  any  particular. 

Law  Enforcement. — The  Federal  Food  and  Drug  Act  ap- 
plies only  to  foods  imported  or  for  interstate  shipment.  For 
such  food  products  inspections  are  made  and  enforcement  is 
secured  by  the  United  States  Department  of  Agriculture.  The 
purity  of  foods  sold  within  the  state  is  controlled  by  special 
state  laws  and  these  laws  are  enforced  by  state  officials.  Mass- 
achusetts has  long  maintained  an  efficient  Division  of  Food 
and  Drugs  under  the  State  Department  of  Health.  The 
samples  are  collected  in  various  parts  of  the  state  by  inspec- 
tors, each  sample  is  numbered  by  the  inspector  who  places  it 
in  a  locker  in  the  partition  wall  of  the  laboratory.  The  in- 
spector himself  never  enters  the  laboratory  but  opens  the 
locker  from  the  outside.     Later  the  locker  is  opened  from  the 


FOOD    CONTROL  213 

inside  by  the  laboratory  technician  and  an  analj^sis  is  made, 
the  report  being  rendered  on  the  basis  of  the  number  used. 
Tn  this  way  every  suspicion  of  collusion  between  the  inspector 
and  analyst  is  avoided. 

The  state  laws  are  usually  similar  to  the  Federal  Food  and 
Drug  Act  but  frequently  include  additional  regulations  re- 
garding special  foods  like  milk,  butter,  sausages,  etc.  The 
state  which  fails  to  make  and  enforce  suitable  laws  is  in  a 
particularly  unfortunate  condition  because  large  food  manu- 
facturers dump  poor  products  upon  it. 

Special  standards  for  foods  like  milk,  butter  and  vinegar 
may  also  be  obtained  by  municipal  ordinance  and  such  foods 
may  be  examined  in  the  city  public  health  laboratory.  The 
most  common  local  ordinance  is  that  governing  the  sale  of 
milk,  the  skimming  or  watering  of  which  is  determined  by  a 
variation  from  the  normal  proportion  of  the  constituents  pro- 
duced by  such  a  process.  The  composition  of  normal  milk  is 
as  follows :  Sugar  4.7%  ;  fat  3.8%  ;  total  solids,  12.8%  ;  refrac- 
tive index,  37.5;  solids  not  fat,  9%;  specific  gravity,  1.032; 
protein,  3.6%;  ash,  0.7%. 

FOOD  SANITATION 

The  three  most  important  problems  in  securing  clean  food 
involve  the  sanitation  of  milk,  meat  and  prepared  food  sup- 
plies. 

Milk. — Milk  is  used  in  enormous  quantities  as  a  food. 
Parker  believes  (City  Milk  Supply,  by  H.  M.  Parker,  McGraw- 
Hill  Book  Co.,  1917)  that  about  5.16  billion  pounds  of  market 
milk  are  consumed  in  this  country  annually.  This  means 
that  the  average  American  consumes  his  own  weight  in  market 
milk  every  year.  Of  course,  children  use  relatively  more  than 
adults.  The  total  quantity  of  milk  used  in  the  United  States 
including  milk  which  is  manufactured  into  butter,  cheese,  and 
other  materials  is  estimated  to  be  77.4  billion  pounds  per  an- 
]ium.     This  is  about  750  pounds  per  person. 


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216  HYGIENE:     DENTAL   AND   GENERAL 

It  is  difficult  to  keep  milk  in  a  sanitary  condition  because  it 
is  not  a  clear  fiuid  but  a  suspension  which  hides  dirt  readily. 
It  is  a  good  medium  for  bacteria  to  grow  in,  so  that  they  rap- 
idly increase  unless  the  milk  is  kept  at  a  low  temperature. 
Moreover,  milk  must  be  produced  at  a  considerable  distance 
from  the  point  where  it  is  finally  used.  Some  of  our  large 
cities  get  milk  from  farms  300  miles  distant.  And  it  is  par- 
ticularly important  that  it  should  be  kept  clean  because  milk 
is  the  one  animal  food  which  is  eaten  raw  in  great  quantities. 

Bacteria  which  are  not  disease-producing  cause  two  kinds 
of  changes  in  milk,  putrefaction  and  fermentation.  Fermen- 
tation usually  results  from  the  action  of  the  lactic  acid  bacil- 
lus and  produces  the  normal  condition  of  sour  milk  by  break- 
ing down  the  milk  sugar  into  lactic  acid.  Milk  sours  be- 
cause the  condition  or  time  of  storage  has  favored  the  develop- 
ment of  acid  forming  bacteria,  its  taste  may  be  disagreeable 
but  it  is  not  injurious  to  the  health.  Indeed  specially  fer- 
mented milk  has  been  recommended  as  healthful.  When  milk 
undergoes  putrefaction  the  proteins  are  attacked  by  bacteria. 
Such  milk  is  alkaline  in  reaction  and  bitter  to  the  taste.  It 
may  be  injurious  to  health. 

There  are  always  many  harmless  bacteria  in  milk  but  it  may 
also  contain  the  germs  of  communicable  diseases.  Everyone 
has  heard  of  milk  borne  epidemics.  Diseases  from  animals  pro- 
ducing milk  epidemics  include  tuberculosis,  milk  sickness, 
malta  fever,  hoof  and  mouth  disease,  contagious  abortion,  and 
various  streptococcus  infections.  The  diseases  which  may  be 
transmitted  from  man  in  milk  are  tuberculosis,  typhoid  fever, 
scarlet  fever,  diphtheria,  septic  sore  throat,  dysentery  and 
diarrhea.  The  germs  of  these  diseases  increase  in  number 
rather  than  die  out  in  milk  and  it  is  extremely  important  that 
both  the  cows  and  the  milk  handlers  should  be  free  from  such 
diseases. 

An  idea  of  the  details  which  have  to  be  considered  in 
producing  clean  milk  may  be  obtained  from  an  examination 


FOOD    CONTROL 


217 


of  the  "Official  Score  Card,"  used  by  the  United  States  De- 
partment of  Agriculture  for  the  purpose  of  rating  dairy 
farms.     (See  pp.  214  and  215.) 

The  problems  of  the  health  department  do  not  end  here 
however,  because  the  milk  must  be  kept  cool  and  clean  from 


TIML    AND    TE.MPLRATURE.     FOR 
nlo°  MILK    PA5TLURIZATI0N. 


/O'  10'  30  ifO' 

Tl  ME.    IN    MINUTL5 

Fig.  30. — Chart  showing-  the  time  and  temperatures  at  which  bacteria  are  killed  and 
at  which  the  quality  of  the  milk  is  changed. 


218  HYGIENE:  DENTAL  AND  GENERAL 

the  time  it  leaves  the  farm  until  it  reaches  the  consumer. 
Frequently  milk  is  a  long-  time  in  transit  and  often  it  is  re- 
bottled  before  being  finally  delivered. 

Pasteurization  has  greatly  improved  the  milk  supply  of 
many  cities  as  it  has  become  more  and  more  widely  adopted. 
This  process  of  heating  the  milk  to  a  temperature  of  from 
64°  to  68°  Centigrade  for  20  minutes  kills  most  non-spore- 


Fig.  31. — Milk  may  be  pasteurized  at  home  by  setting  the  bottles  in  a  deep 
dish  of  water  or  double-cooker  and  raising  the  temperature  of  the  milk  to  145°  for 
a  half  hour. 

bearing  organisms.  It  is  most  valuable  when  the  milk  is  pas- 
teurized in  the  final  container.  If  the  temperatures  do  not 
go  above  68°  Centigrade  the  composition  and  taste  of  the  milk 
are  not  changed. 

Graded  Milk. — Terms  which  are  often  used  to  describe 
various  grades  of  milk  are :  Certified  Milk,  Inspected  milk, 
and  Market  Milk. 


FOOD    CONTROL  219 

The  American  Association  of  Medical  Milk  Commissions 
(See  Public  Health  Reports  No.  85,  May  1,  1912)  has  set  the 
standards  for  Certified  Milk.  Such  milk  is  certified  by  a 
Medical  Milk  Commission  to  be  produced  from  healthy,  tuber- 
culin-tested cattle  which  are  subject  to  veterinary  inspection. 
The  milkers  and  the  milk  handlers  are  given  physical  exami- 
nations to  see  that  they  have  no  communicable  diseases,  the 
cattle  are  kept  clean  and  are  given  proper  food;  proper  sani- 
tary precautions  are  taken  during  milking,  the  barn  is  clean, 
the  milk  is  cleanly  bottled  at  the  dairy  and  kept  cold.  The 
bacterial  count  of  such  milk  is  less  than  10,000  per  c.c.  It  is 
delivered  within  36  hours  after  it  is  produced. 

Inspected  Milk  is  of  a  somewhat  lower  grade  but  it  comes 
from  tested  cows  and  it  is  secured  and  marketed  under  cleanly 
conditions.  The  bacterial  count  of  such  milk  is  less  than 
100,000  bacteria  per  c.c. 

The  term  Market  Milk  is  often  used  to  describe  milk  which 
is  below  the  standard  of  either  of  the  above  grades. 

Some  years  ago  New  York  City  began  to  grade  its  milk  sup- 
ply and  this  practice  has  now  been  taken  up  by  many  other 
cities  with  profitable  results.  Grading  milk  has  the  advantage 
of  allowing  the  purchaser  to  know  the  exact  quality  of  the  milk 
he  is  buying  and  of  enabling  the  dairyman  to  get  a  higher 
price  for  a  superior  product.  The  table  on  pp.  220  and  221 
from  Piihlic  Health  Leaflet  No.  1  of  the  City  Health  Depart- 
ment shows  the  standard  set  for  milk  of  the  various  grades  A, 
B,  and  C. 

Remade  Milk. — Remade  milk  is  a  new  product  which  is 
being  used  by  hospitals  and  other  institutions  wdth  good  re- 
sults. This  is  made  by  mixing  dehydrated  skimmed  milk 
(milk  powder)  and  unsalted  butter  or  milk  fat  with  water 
in  an  h'omogenizer.  By  this  process  milk  may  be  dehydrated 
in  dairy  regions  far  from  the  cities  and  remade  in  the  large 
centers  of  population  producing  a  clean,  and  inexpensive 
product.  Remade  milk  has  a  low  bacterial  count  and  a  good 
cream  line.     It  is  not  easilv  distinguishable  from  fresh  milk. 


220 


HYGIENE:     DENTAL   AND   GENERAL 


REGULATIONS  GOVERNING  THE  GRADES  AND  DESIGNATION  OF  MILK 

The  following  classifications  apply  to  milk  and  cream.     The  regulations  regardinp 


GRADES  OF 

MILK  OR 

CREAM 

WHICH  MAY 

BE  SOLD  IN 

THE  CITY  OF 

NEW  YORK 


DEFINITION 


TUBERCULIN 
TEST  AND 
PHYSICAL 
CONDITION 


BACTERIAL  CONTENTS 


Milk  or  Cream 
(Raw) 


Grade  A  milk  or  cream  (raw)  is 
milk  or  cream  produced  and  handled 
in  accordance  with  the  requirements, 
rules  and  regulations  of  the  Depart- 
ment of  Health  for  that  grade. 


1  Only  such 
cows  shall  be  ad- 
mi  t  ted  to  the 
herd  as  have  not 
reacted  to  a 
diagnostic  injec- 
tion of  tubercu- 
lin and  are  in 
good  physical 
condition. 

2.  All  cows 
shall  be  tested 
annually  with 
tuberculin  and 
all  reacting  ani- 
mals shall  be  ex- 
cluded from  the 
hcrd- 


Milk'or  Cream 
(Pasteurized) 


Grade  A  milk  or  cream  (pasteur- 
ized) is  milk  or  cream  produced, 
handled  and  pasteurized  in  conformity 
with  the  requirements,  rult-s  and  regu- 
lations of  the  Department  of  Health 
for  that  grade. 


No  tuberculin 
test  required  but 
cows  must  be 
healthy  as  dis- 
closed by  physi- 
cal examination 
made  annually. 


Milk  or  Cream 
(Pasteurized) 


GRADE  C 

Milk  or  Cream 
(Pasteurized) 
(for  cooking 
and  manu- 
facturing pur- 
poses only). 


Grade  B  milk  or  cream  (pastteur- 
ized)  is  milk  or  cream  produced, 
handled  and  pasteurized  in  conformity 
with  the  requirements,  rules  and  regu- 
lations of  the  Department  of  Health 
for  that  grade 


Grade  C  mitk  or  cream  (pasteur- 
ized) is  milk  or  cream  pro'duced, 
handled  and  pasteurized  inmccordance 
with  the  requirements,  rules  and  regu- 
lations of  the  Department  of  Health. 
for  that  grade 


No  tuberculin 
test  required  but 
cows  must  be 
healthy  as  dis- 
closed by>  physi- 
cal examination 
liiadc  annually. 


No  tuberculin 
test  required  but 
cows  must  .  be 
healthy  as  dis- 
closed by  physi- 
cal examination 
made  annually 


Grade  A  milk  (Raw)  shall  not 
contain  more  than  30,000  bac- 
teria per  c.  c.  and  cream  more 
than  150,000  bacteria  per  o.  o. 
when  delivered  to  the  consumer 
or  at  any  time  prior  to  such  de- 
livery 


Grade  A  milk  (pasteurized) 
shall  not  contain  more  than  30,- 
000  bacteria  per  c.  c.  and  cream 
(pasteurized)  more  than  150,000 
bacteria  per  c.  c.  when  delivered 
to  the  consumer  or  at  any  time 
after  pasteurization  and  prior  to 
such  delivery. 

No  milk  supply  averaging 
more  than  200,000  bacteria  per 
c.  c.  shall  be  pasteurized  in  this 
city  for  sale  under  this  designa- 
tion. 

No  milk  supply  averaging 
more  than  100,000  bacteria  per 
c.  r  shall  be  pasteurized  outside 

ot   this   oity   for  calo  la   thia   city 

under  this  iesignation, 


No  milk  under  this  »rade  shall 
contain  more  than  1C0,000  bac- 
teria per  c.  c.  and  no  cream  shall 
contain  more  than  500,000  bac- 
teria per  c.  c.  when  dehvered  to 
the  consumer  or  at  any  time 
after  pasteurization  and  prior  to 
such  dehvery. 

No  milk  supply  averaging 
more  than  1,500,000  bacteria  per 
c.  c.  shall  be  pa.steurized  in  this 
city  for  sale  under  this  desig- 
nation. 

No  milk  supply  averaging 
more  than  300,000  bacteria  per 
c.  c.  shall  be  pasteurized  outside 
of  this  city  for  sale  under  this 
designation. 


Milk  or  crea(o  of  this  grade 
shall  not  contain  an  ezoeaaiTe 
'number  of  bacteria. 


NOTE.— Sour  milk,  buttermilk,  sour  cream,  kumyss,  matzopn    zoolao  ""i^"^'^ 
and  shall  be  pasteurized  before  being  put  through  the  process,  of  souring,    bour  cream  snau 


FOOD    CONTROL 


221 


AWD  CREAM  WHICH  MAY  BE  SOLD  IN  THE  CITY  OF  NEW  YORK 

bacterinl  cnntont  and  time  of  delivery  do  not  apply  to  sour  cream. 


n\TRV 
INSI'EC-rH'iN' 
REQlISITKrf 


Dairies  are  in- 
f^pected  at  least 
four  times  a  year 
by  Department  in- 
spectors. 

.Ml  requisites 
indicated  on  dairy 
report  card  used_ 
by  Department  of 
Health  must  be 
complied  v:\th 


Dairies  arc  in- 
spected at  least 
four  times  a  year 
by  Department  in- 
spectors. 

.\11  requisites 
indicated  on  dairy 
report  card  used 
by  Department  of 
Health,  except  tu- 
berculin testing  of 
cattle,  must  be 
complied  with 


Dairies  must  be  ^ 
inspected  at  least  ' 
nnce  a  year  by  in-  j 
spectors  employed 
by  operator  of 
creamery  or  pas- 
teurizing plant  to 
which  milk  is  de- 
livered. These  in- 
epectors  must  be 
persona  satisfac- 
tory to  the  New 
York'City  Depart- 
ment of  Health, 
and  reports  sub- 
mitted on  ap- 
proved dairy  re- 
port cards  must  be 
kept  on  file  at 
<:reamery  or  plant. 
Inspections  are 
supervised  or 
<:hecked  by  De- 
partment inspect- 
ors at  intervals. 


Dairies  not 
regularly  in- 
spected.  Only  a 
small  quantity  of 
milk  of  this  grade 
is  ever  sold  ia  the 
city. 


TIME  OF 
DELIVEllY 


Shall  be  de- 
livered within  36 
liours.  after  pro- 
duction 


Sh.all  be  de- 
livered within  30 
hours  after  pas- 
teurization. 


Vnlcss  other- 
vnat  specified  in 
the  permit  this 
milk  or  cream 
shall  be  delivered 
to  the  con.sunier 
only  in  bottles 


Unless  other- 
wise specified  in 
the  permit  this 
milk  or  cream 
shall  be  delivered 
to  the  consumer 
only  in  bottles. 


Milk  shall  be 
delivered  within 
48  hours  and 
cream  within  72 
hours  after  pas- 
teurization. 


Milk  shall  be 
delivered  within 
48  hours  and 
cream  within  72 
hours  after  pas- 
teurization 


May  be  de- 
livered in  cans 
or  bottles. 


May  be  de- 
livered in  cans 
only 


Outer  caps  of  bottles  shall 
be  white  and  shall  contain 
the  words  Grade  A,  Raw.  in 
black  letters  in  large  type, 
and  shall  state  the  place  of  pro- 
duction, date  of  shipment  and 
the  name  and  address  of  the 
dealer 


Outer  caps  of  bottles  shall 
be  white  and  shall  contain 
the  words  Grade  A  in  black 
letters  in  large  type,  date  and 
hours  between  which  pasteur- 
ization was  completed,  place 
where  pasteurization  was  per- 
formed, name  of  the  person, 
firm  or  corporation  offering 
for  sale.  seUmg  or  delivering 
same 


Outer  caps  of  bottles  con- 
taiuing  milk  and  tags  affixed 
to  cans  containing  milk  or 
cream  shall  be  white  and 
marked  "Grade  B"  in  bright 
green  letters  in  large  type, 
date  pasteurization  was  com- 
pleted, place  where  pasteur- 
ization was  performed,  name 
of  the  person,  firm  or  cor- 
poration offering  for  sale, 
selling  or'  deUvering  same. 
Bottles  containing  cream  shall 
be  labeled  with  caps  marked 
"Grade  B"  in  bright  green 
letters,  in  large  type  and 
shall  give  the  place  and  date 
of  bottling  and  shall  give  the 
name  of  person,  firm  or  cor- 
poration offering  for  sale, 
selling  or  delivering  same. 


Tags  affixed  to  cans  shall 
be  white  and  shall  be  marked 
in  red  with  the  words  "Grade 
C"  in  large  type  and  _  \'for 
cooking"  in  plainly  visible 
type,  and  cans  shall  have 
properly  sealed  metal  collars, 
painted  red  on  necks. 


Only  such 
milk  or  cream 
shall  be  re- 
garded as  pas- 
teurized as  has 
been  subjected 
to  a  tempera- 
ture of  142-145 
deg.  Fahr.  for 
not  less  than  30 
minutes 


Only  s  u  ch 
milk  or  cream 
shall  be  re- 
garded as  pas- 
teurized as  has 
been  subjected 
to  a  tempera- 
ture of  142-145 
deg.  Fahr.  for 
nut  less  than  30 
minutes. 


Only  such 
milk  or  cream 
shall  be  re- 
garded as  pas* 
teurized  as  has 
been  subjected 
to  a  temperature 
of  142-145  deg. 
Fahr.  for  not  1686 
than  30  minutes. 


products  shall  not  be  made  from  any  milk  of  a  leas  grade  than  that  designated  for  "Grade  B" 
not  contain  a  less  percentage  of  fata  than  that  designated  for  cream 


222  HYGIENE:     DENTAL    AND    GENERAL 

Meat. — Meat  is  inspected  by  Federal,  State  and  Local 
Health  Agents,  and  in  large  abattoirs  an  inspection  both  be- 
fore and  after  killing  is  made.  One  reason  for  making  such 
an  inspection  is  to  see  that  the  animal  is  free  from  such  dis- 
eases as  tuberculosis,  anthrax,  trichinosis,  actinomycosis,  tape- 
worm, septic  and  pyemic  conditions.  Later  inspections  of 
meat  are  to  make  sure  that  the  meat  has  not  become  decom- 
posed or  infected.  There  is  also  a  supervision  over  the  proc- 
esses of  slaughter  to  see  that  the  death  of  the  animal  is  im- 
mediate and  painless,  that  there  is  an  immediate  withdrawal 
of  blood,  that  the  intestines,  hide  and  hair  are  promptly  re- 
moved and  that  there  is  immediate  cooling. 

Dang-ers  in  Meat. — The  important  health  dangers  which 
exist  where  meat  is  not  inspected  are  due  to  the  following 
causes : 

(1)  Paratyphoid  Bacilli. — If  animals  have  had  fevers,  diar- 
rhea or  local  suppurations  and  especially  if  the  conditions  of 
slaughter  are  not  clean,  meat  maj^  have  picked  up  these  or- 
ganisms of  the  typhoid  group,  which  produce  diarrheas  of 
varying  intensities. 

(2)  Bacillus  Botulinus. — This  bacillus,  which  produces 
botulism,  is  an  anaerobic,  spore-forming  saprophyte,  which 
grows  outside  the  body  and  may  infect  meat  and  develop  in 
sausages  which  are  not  kept  under  sanitary  conditions.  This 
organism  produces  an  exotoxin  which  causes  the  typical 
symptoms  of  botulism  when  the  infected  food  is  eaten. 

(3)  Tricliina  Spiralis. — The  small  roundworm  which  pro- 
duces trichinosis  has  a  normal  cycle  in  rats  but  the  disease 
may  extend  to  swine.  When  this  happens  the  larvae  become 
encysted  in  the  muscle  of  the  pig  producing  a  condition  known 
as  "measly  pork."  When  such  pork  is  eaten  without  being 
thoroughly  cooked  the  larvae  develop  into  mature  worms  in 
the  human  intestines.  Each  female  produces  about  500  living 
young  and  these  embryos  penetrate  the  tissues  of  the  bowels 
and  find  their  way  into  the  muscle  of  the  human  subject  pro- 
ducing pain,  fever,  soreness  and  other  symptoms  of  the  disease. 


FOOD    COXTKOL  223 

Microscopic  examination  of  meat  is  fairly  successful  in  de- 
tecting the  presence  of  these  parasites.  All  pork  should  be 
cooked  until  it  is  thoroughly  white  and  hams  should  be  boiled 
for  %  hour  for  every  kilogram  weight  to  kill  the  organisms. 

(4)  Tccnia  Solium. — The  encysted  larvas  (bladder  worms) 
of  the  pork  tapeworms  may  be  eaten  in  pork.  This  infection 
is  particularly  dangerous  because  the  larvas  develop  in  man 
and  may  find  their  way  to  important  parts  of  the  body  such 
as  the  eye,  or  the  brain. 

(5)  Tccnia  Saginnta. — This  tapeworm  occurs  only  in  cat- 
tle and  in  man.  The  larvas  are  found  embedded  in  beef  and 
when  such  meat  is  eaten  they  develop  in  the  human  intestines. 
This  tapeworm  is  not  dangerous  although  it  causes  anemia 
and  is  often  difficult  to  expel.  Man  is  infected  from  un- 
cooked beef  while  cattle  are  infected  by  eggs  passed  in  hu- 
man feces. 

(6)  Tcenia  Ecliinococcus. — This  minute^  tapeworm  of  the 
dog  frequently  infests  cattle,  swine,  horses  and  sheep,  reach- 
ing the  digestive  tract  of  the  new  host  in  the  form  of  the  eggs 
which  are  passed  in  the  feces  of  the  dog.  The  embryoes 
develop  in  the  digestive  tube,  pierce  the  mucosa  and  become 
encj^sted  in  various  tissues  and  organs  of  the  body.  jMan  like 
the  other  animals  mentioned  is  infected  from  the  dog  by  in- 
gesting eggs  which  are  passed  in  the  feces. 

(7)  Ptomaine  Poisoning. — Much  less  is  heard  recently  of 
ptomaine  poisoning  which  has  been  regarded  as  being  pro- 
duced by  a  poisonous  substance  formed  in  the  decomposition  of 
proteins.  Many  cases  of  supposed  ptomaine  poisoning  have 
l)een  found  to  be  infections  or  intoxications  produced  by  such 
organisms  as  paratyphoid  or  botulinus. 

Prepared  Food. — The  sanitation  of  prepared  food  is  secured 
through  the  supervision  of  restaurants,  food  stores,  and  other 
places  where  food  is  sold.  The  score  card  shown  on  page  22-1 
for  food  stores  used  by  the  Health  Department  of  the  City  of 
Boston  shows  the  factors  of  cleanliness  which  are  considered. 


224 


HYGIENE  :     DENTAL    AND    GENERAL 


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FOOD    CONTROL  _  225 

Two  factors  not  mcutioiiecl  in  such  a  score  card  but  of  ex- 
treme importance  in  food  sanitation  at  restaurants  and  hotels 
are  the  physical  examination  of  food  handlers  and  the  method 
of  disJi  washing.  A  waiter  or  food  handler  who  is  tuber- 
culous or  who  is  a  typhoid  carrier  may  infect  food  prepared 
in  the  most  cleanly  kitchen.  The  case  of  one  such  carrier, 
' '  Typhoid  Mary, '"'  has  become  famous.  No  person  harboring 
the  germs  of  typhoid  or  any  other  infectious  disease  should  be 
allowed  to  handle  food.  The  startling  discoveries  of  Dr. 
Gumming,  showing  how  dishes  which  are  not  scalded  may  con- 
vey respiratory  diseases,  are  described  in  the  discussion  of 
influenza.  Both  in  the  home  and  in  public  eating  places  the 
germs  of  tuberculosis,  common  colds,  influenza,  septic  sore 
throat  and  other  diseases  are  doubtless  carried  from  diseased 
persons  to  healthy  individuals  on  unscalded  dishes  much  more 
often  than  we  have  previously  realized. 


CHAPTER  XII 

WATER  SUPPLY 

The  danger  of  transmitting  disease  by  polluted  water  has 
been  well  recognized  since  the  epidemic  of  the  Broad  Street 
Well  in  1854.  We  know  now,  as  they  did  not  then,  that  the 
danger  is  not  from  a  particular  and  peculiar  poisonous  sub- 
stance, but  rather  from  the  germs  of  infectious  disease  which 
remain  alive  in  the  water  and  reproduce  the  disease  by  multi- 
plying in  the  digestive  tract  of  the  individual  who  has  drunk 
thereof.  Water-borne  epidemics  of  typhoid  fever,  cholera,  and 
diarrhea  have  been  so  numerous  and  so  important  that  the 
people  at  large  now  have  a  very  keen  appreciation  of  the 
danger  from  a  polluted  water  supply. 

Although  freedom  from  disease  germs  is  a  most  important 
characteristic  of  good  water,  there  are  many  other  important 
considerations  in  securing  a  city  water  supply.  Indeed  if 
disease  germs  were  the  only  menace,  that  danger  could  be 
avoided  by  always  boiling  water  before  drinking  it.  Such  a 
precaution  is  used  by  travelers  and  explorers  where  the  source 
of  water  is  unknown.  In  China,  where  the  population  is 
dense,  most  of  the  wells  are  polluted  and  the  people  are  saved 
from  intestinal  disease  by  their  tea-drinking  habit,  through 
which  they  avoid  the  use  of  raw  or  unboiled  water. 

Important  as  water  is  for  the  body  there  are  many  ways  in 
which  it  is  used  outside  the  diet  and  it  is  because  so  much  is 
needed  that  it  is  difficult  to  secure  a  satisfactory  supply.  The 
average  American  city  uses  100  gallons  of  water  a  day  for 
every  inhabitant.  Water  has  the  property  of  picking  up  dirt 
so  readily  and  the  outlying  districts  of  cities  become  settled 
so  soon  that  the  water  shed  or  drainage  basin  from  which 
water  would  naturally  be  secured  contains  many  habitations 

226 


WATER    SITPPLY  227 

and  the  opportunities  for  pollution  with  hnman  or  animal 
waste  are  innumerable. 

What  Is  Good  Water? — The  characteristics  of  a  good  water 
supply  may  be  enumerated  as  follows : 

1.  It  should  he  free  from  the  germs  of  infectious  disease. 

2.  It  should  he  free  frmn  poisonous  metals,  particularly 
lead.  It  is  well  known  that  lead  is  a  cumulative  poison  which 
is  readily  taken  up  by  the  body  in  small  quantities  and  which 
has  serious  effects  particularly  upon  the  stomach  and  the  nerv- 
ous system.  "'Painter's  colic"  and  "wrist-drop"  are  typical 
symptoms  of  this  type  of  poisoning.  Some  waters  have  a 
much  greater  solvent  action  upon  lead  pipe  than  others. 

3.  The  water  should  he  of  suitahle  temperature,  certainly 
less  than  80°F.  If  the  water  is  too  warm  it  will  not  be  used 
as  much  as  it  should  be  for  drinking  purposes. 

4.  The  ivater  should  he  loiv  in  color,  otherwise  it  will  not  be 
acceptable.  Color  may  be  harmless  but  a  highly- colored  water 
will  not  be  generously  used. 

5.  It  should  he  clear,  i.e.,  free  from  suspended  matter,  like 
sand  or  clay. 

6.  7^  shoidd  he  odorless.  The  odor  of  water  most  frequently 
comes  from  small  or  microscopic  plants  which  grow  in  the 
lake  or  reservoir  and  which  of  themselves  are  entirely  harm- 
less. The  odors  which  tliey  produce,  however,  are  distinctly 
disagreeable  and  may  make  the  water  oft'ensive. 

7.  The  ivater  should  not  he  too  hard,  since  hard  water  makes 
laundering  particularly  difficult.  This  is  caused  by  the  re- 
action of  the  calcium  or  magnesium  salts  of  hard  water  in  dis- 
placing the  sodium  of  soap.'  Such  a  reaction  forms  a  pre- 
cipitate of  the  above  mentioned  salts  and  enough  soap  must 
be  added  to  use  up  all  the  calcium  and  magnesium  in  the  water 
before  any  lather  is  produced.  Hard  water  is  therefore  un- 
pleasant to  use  on  the  flesh  and  costly  for  laundering  purposes. 

8.  It  should  he  practically  free  from  iron.  Otherwise 
clothes  will  be  stained  or  "rusted"  in  the  laundering  process. 


228  HYGIENE :     DENTAL   AND   GENERAL 

Sources  of  Water  Supply. — There  are  two  kinds  of  water 
supplies,  surface  waters  and  ground  waters.  We  can  better 
appreciate  their  differences  if  we  follow  the  history  of  water 
after  it  falls  as  rain.  It  may  fall  directlj^  into  rivers  or  lakes, 
or  it  may  reach  them  by  running  over  the  surface  of  the 
ground.  More  often  it  reaches  them  by  soaking  through  the 
soil  just  beneath  the  surface,  for  gi^ound  water  is  always  in 
motion,  moving  from  0.2'  to  20'  per  day,  toward  visible  or 
underground  rivers  or  in  the  direction  of  their  flow.  Water 
taken  directly  from  rivers  and  lakes  or  temporarily  stored  in 
reservoirs  constitutes  a  surface  water  supply. 

Surface  Wate?',  which  has  washed  over  the  ground  and 
Avhich  in  rivers  and  lakes  furnishes  the  home  for  innumerable 
plants  and  animals,  naturally  contains  many  things  besides 
hydrogen  and  oxygen;  in  fact  chemically  pure  water  is  diffi- 
cult to  secure  even  in  the  laboratorj^  In  nature  water  which 
appears  perfectly  clear  to  the  eye  may  reveal  many  things 
upon  chemical  and  microscopic  examination.  It  contains  dis- 
solved oxygen,  upon  which  the  fish  and  other  animals  live, 
nitrates  and  other  salts  used  by  plants,  carbon  dioxide  and  per- 
haps ammonia,  marsh  gas  and  other  chemical  substances.  An 
examination  with  the  microscope  reveals  particles  of  dirt, 
bacteria,  minute  plants  and  animals,  bits  of  wood  and  fibers 
of  one  sort  or  another.  If  this  water  has  passed  over  polluted 
ground,  filth  and  disease  germs  may  be  added  to  its  contents. 

Ground  Water  is  obtained  from  wells  of  various  depths  and 
may  be  free  from  many  of  these  substances,  which  are  caught 
and  held  back  as  the  water  strains  through  the  soil.  Sandy 
or  gravelly  soil  is  the  best  filter  for  water,  and  in  passing 
through  100  feet  of  sandy  soil  water  will  be  purified  for  a  con- 
siderable period.  Finally,  however,  even  this  soil  would  be- 
come polluted  and  a  well  100  feet  from  a  privy  or  other 
source  of  pollution  would  be  endangered.  When  in  place  of 
sand  we  have  a  broken  formation,  as  is  the  case  with  limestone 
or  some  types  of  ledge,  there  may  be  a  break  having  a  rivulet 
by  which  pollution  may  reach  the  well  directly. 


WATER   SUPPLY 


229 


The  difference  between  surface  wells  and  deep  wells  is  one 
of  character  and  not  primarily  one  of  depth.  A  surface  ivell 
is  one  which  does  not  reach  through  the  first  impenetrable 
layer  of  soil ;  while  a  deep  well  does  go  through  the  impervious 
layer  and  furnishes  its  water  from  the  water  table.  A  deep 
well  may  be  a  quiet  well  from  which  the  water  is  pumped,  or 
it  may  be  an  artesian  well  from  which  the  water  flows  freely. 
The  artesian  well  is  produced  by  a  water  pressure  beneath 


Fig.  32. — Wells  may  be  polluted  by  water  which  soaks  through  the  soil  from 
privies  or  cesspools.  The  danger  of  pollution  is  less  in  sand  and  gravel  soil  but 
these  may  finally  become  saturated  and  permit  infection.  (The  Human  Mecha- 
nism.) 


the  imijervious  layer  of  soil  which  is  sufficient  to  throw  water 
to  the  surface. 

Well  water  has  been  used  for  generations.  It  is  usually 
clear,  cold  and  sparkling  and  most  people  believe  that  well 
waters  arc  almost  always  safe.  The  contrary,  however,  is 
frequently  the  case,  especially  where  wells  are  dug  in  un- 
sewered  villages  where  the  soil  is  heavily  polluted.  In  fact 
a  clear  and  sparkling  water  may  be  more  dangerous  than  the 
yellow  and  smelly  water  of  a  stagnant  pond  for,  as  we  shall 
see  later,  water  purifies  itself  by  storage.     The  water  from 


230  HYGIENE:     DENTAL    AND    GENERAL 

deep  wells  is  usually  more  reliable  than  that  from  shallow 
wells  because  it  has  been  in  the  ground  longer  and  has  worked 
its  way  through  the  soil  for  a  long  distance.  Any  student 
of  bacteriology  knows  that  a  glass  of  water  may  contain 
thousands  of  typhoid  bacilli  without  showing  the  slightest 
trace  of  sediment.  "When  people  generally  realize  this  they 
will  cease  to  judge  the  quality  of  drinking  water  by  its  ap- 
pearance. 

WATER  ANALYSIS 

A  careful  examination  is  necessary  to  really  determine 
the  quality  of  a  water  supply.  Such  an  examination  in- 
cludes four  factors.  A  study  of  (1)  the  environment,  (2)  a 
bacteriological  examination,  (3)  a  microscopic  examination, 
and  (4)  a  chemical  examination. 

1.  Environment. — In  order  to  estimate  the  value  of  water 
the  sanitarian  must  know  the  nature  of  the  water  shed  from 
which  it  comes ;  that  is,  the  number  of  inhabitants  in  the  drain- 
age area,  and  the  nature  of  the  soil  and  slope  of  the  drainage 
basin.  A  laboratory  examination  of  the  water  at  some  par- 
ticular time  might  be  satisfactory  and  yet  if  the  water 
came  from  a  populous  district  with  a  clay  soil  and  steep 
slopes,  a  heavy  rain  might  wash  great  quantities  of  pollution 
into  the  stream  or  lake. 

2.  Bacteriological  Study. — The  second  step  is  the  bacte- 
riological examination  of  a  properly  secured  sample  of  the 
Avater.  By  plating  out  the  water  in  different  dilutions  the 
total  number  of  bacteria  may  be  determined  and  by  using 
different  temperatures  for  incubating  the  petri  dish  plates  the 
number  of  water  bacteria  can  be  contrasted  with  the  number 
that  grow  well  at  body  temperature. 

Tests*  are  also  made  to  determine  the  number  of  bacillus 


'l,aljoratory  directions  for  making  a  complete  water  analysis  may  be  found  in 
"Standard  Methods  of  Water  Analysis"  luiblished  by  the  American  Public  Health 
Association.  Such  directions  would  be  out  of  place  in  a  discussion  for  dental 
practitioners.  Ilovvever.  it  does  seem  advisable  to  describe  the  principles  involved 
in  the   interpretation   of  a  water   analysis. 


WATER    SUPPLY  231 

eoli  in  the  water.  It  is  not  easy  to  detect  tj-phoid  bacilli  or 
other  disease  germs  when  they  are  present  but  the  colon  ba- 
cillus, which  is  a  normal  inhabitant  of  the  intestines,  is  easy 
to  discover  and  determination  of  its  presence  gives  a  good  in- 
dication of  the  pollution  or  purity  of  the  water  in  question. 
Of  the  various  bacteriological  tests  which  are  made  these  two, 
the  total  bacteria  and  the  presumptive  test  for  B.  coli,  are 
the  most  important. 

3.  Physical  Tests. — The  physical  tests  which  are  made  upon 
water  include  an  examination  for  odor,  temperatvire,  color  and 
turbidity. 

The  color  is  expressed  in  parts  per  million  and  is  determined 
by  comparing  the  Avater  with  a  platinum-cobalt  standard. 
True  color  is  produced  by  substances  in  solution,  many  of 
which  come  from  vegetable  tissues  soaking  in  the  water. 

The  turhidity  is  likewise  expressed  in  parts  per  million  and 
is  usually  determined  by  comparing  the  water  with  a  standard 
suspension  of  silica.  It  is  produced  by  finely  divided  sus- 
pended matter  like  clay,  silt  and  microscopic  organisms. 

The  odors  are  described  as  fishy,  vegetable,  aromatic, 
grassy,  earthy,  mould}^,  musty,  disagreeable,  peaty  or  sweetish. 
They  are  caused  bj^  decomposing  organisms,  fermenting  ma- 
terial, or  gases  like  hydrogen-sulphide  or  methane.  Many  of 
the  tiny  green  plants,  particularly  the  diatoms  have  quite  dis- 
tinctive odors. 

It  will  be  seen  from  the  above  that  the  physical  examination 
of  water  tells  much  about  its  condition  but  little  about  its 
sanitary  quality. 

4.  Chemical  Tests. — The  most  important  chemical  tests  from 
the  sanitary  point  of  view  are  the  tests  for  nitrogen  in  its 
various  forms  and  the  test  for  chlorine.  The  nitrogen  tests 
give  us  an  index  of  the  quantity,  the  nature  and  the  freshness 
of  pollution  by  nitrogenous  waste  material.  The  test  for  chlo- 
rine is  a  valuable  indicator  of  pollution  because  in  soils  free 
from  salt  deposits  the  only  source  of  chlorine,  except  for  salt 
mists  1)rought  in  from  the  ocean,  is  the  waste  of  the  body. 


232 


HYGIENE:  DENTAL  AND  GENERAL 


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WATER   SUPPLY  233 

Nitrogen  and  the  Nitrogen  Cycle. — To  understand  the 
meaning  of  the  nitrogen  tests  we  must  recall  for  a  moment 
the  story  of  the  nitrogen  cycle.  We  find  this  important  ele- 
ment going  through  an  endless  chain  of  changes.  Inorganic 
nitrogen  is  taken  up  by  plants  in  its  simple  inorganic  condition 
and  transformed  into  plant  protein  from  which  in  turn  it  is 
transformed  into  animal  protein  by  herbivorous  animals. 
When  these  complex  proteins  from  living  animals  are  left 
exposed  in  the  air  or  in  water  they  return  to  their  simple 
condition  by  a  series  of  definite  oxidation  processes.  In  this 
series  of  changes  the  nitrogen  is  found  consecutively  in  com- 
plex proteins,  albuminoid  substances,  ammonium  salts,  nitrites 
and  nitrates.  Special  microorganisms  carry  out  the  last  two 
steps.  Ammonium  compounds  are  acted  upon  by  nitroso- 
monas  and  oxidized  to  nitrites.  Nitrites  are  oxidized  by  nitro- 
bacter  to  nitrates.  In  making  a  chemical  analysis  of  water 
we  can  determine  the  amount  of  nitrogen  in  these  various 
conditions. 

The  test  for  nitrites  is  particularly  valuable  because  the  test 
itself  is  very  delicate  and  because  nitrogen  passes  through  the 
nitrite  stage  very  quickly.  The  analysis  will  readily  deter- 
mine the  presence  of  0.01  parts  of  nitrites  per  million.  Even 
this  small  quantity  shows  clearly  that  organic  substances  are 
being  broken  up  in  the  water.  This  is  an  indication  of  fresh 
pollution  for  if  the  pollution  were  remote  the  nitrogen  would 
be  found  in  some  of  its  more  stable  compounds. 

The  test  for  free  ammonia  determines  the  amount  of  nitro- 
gen present  in  the  water  as  ammonium  salts,  which  are  readily 
driven  off  on  the  direct  distillation  of  slightly  alkaline  water. 
A  large  amount  of  free  ammonia  also  indicates  pollution,  al- 
though it  may  be  remote. 

The  test  for  Albuminoid  ammo  mi  measures  the  amount  of 
ammonia  set  free  from  nitrogenous  organic  matter  by  the 
action  of  boiling  alkaline  potassium  permanganate.  This  is 
therefore  a  good  index  of  the  amount  of  easily  decomposable 
organic  matter  in  the  water.     It  may  come  from  plant  sub- 


234  HYGIENE  :     DENTAL   AND    GENERAL 

stances  or  from  animal  wastes  but  when  it  is  from  a  vege- 
table source  the  water  is  usually  colored  and  the  nitrogenous 
material  is  more  stable.  It  therefore  follows  that  a  colorless 
water  should  contain  less  albuminoid  ammonia  than  the  yel- 
low waters  of  natural  storage  reservoirs. 

.  Nitrogen  in  the  form  of  nitrates  is  the  final  product  of  the 
process  of  oxidation  or  mineralization.  These  are  the  stable 
compounds  which  are  used  as  food  by  plants  in  building  up 
the  nitrogen  to  the  organic  form.  If  the  nitrates  are  high 
it  indicates  that  a  good  deal  of  nitrogen  has  gone  through  the 
mineralizing  process  and  therefore  a  high  figure  may  indicate 
pollution  even  though  it  be  remote.  Good  ground  water  may 
contain  more  nitrates  than  surface  water  because  the  nitrates 
of  ground  water  are  not  used  up  by  growing  plants. 

By  a  continued  studj''  of  water  supplies  of  various  sorts  a 
set  of  standards  or  limits  can  be  set  as  to  the  amount  of  these 
various  substances  a  good  water  may  contain,  although  in 
every  case,  the  final  interpretation  of  the  chemical  analysis 
should  be  made  by  an  expert.  In  general  a  safe  water  should 
not  contain  more  of  these  substances  than  is  indicated  in  the 
following  table. 

XITEOGEN  LIMITS  IN  A  SAFE  WATER  SUPPLY  EXPRESSED 
IN  PARTS  PER  MILLION 

Nitrogen   as   albuminoid   ammonia   0.15    (colorless   water)    0.4    (colored 

water). 
Nitrogen  as  free   ammonia   0.1-3. 
Nitrogen  as  nitrites   0.01. 
Nitrogen  as  nitrates.   1.    (surface  water)      2.    (ground  Avater). 

Chlorine. — Chlorides  occur  mostly  as  the  sodium  salt  and 
the  results  are  usually  expressed  in  terms  of  chlorine.  As 
stated  above  waters  coming  from  soils  free  from  salt  deposits 
receive  chlorine  from  onAy  two  sources,  salt  mists  blown  in 
from  the  ocean  and  animal  wastes,  principally  urine.  (Human 
urine  contains  about  one  per  cent  sodium  chloride.)  It  there- 
fore foUows  that  un]^o]luted  waters  near  the  ocean  would  con- 


WATER    SUPPLY  235 

tain  more  chlorine  than  those  at  some  distance  from  the  coast. 
By  the  analysis  of  a  large  number  of  samples  from  waters  of 
known  purity  in  various  parts  of  a  coast  state  the  normal 
amount  of  chlorine  for  each  particular  district  can  be  de- 
termined and  if  a  suspected  water  contains  more  than  the 
"normal"  amount  of  chlorine  it  may  be  justly  concluded  that 
an  additional  amount  has  been  derived  from  pollution.  It 
will  be  seen  that  it  is  not  the  number  of  parts  per  million 
of  chlorine  but  the  relation  of  the  amount  of  chlorine  to 
the  "normal"  which  is  taken  into  consideration  in  inter- 
preting this  chemical  test. 

5.  Microscopic  Analysis. — We  have  seen  that  disagreeable 
tastes  and  odors  commonly  arise  from  the  presence  of  micro- 
scopic plants  and  animals  in  water.  Their  presence  can  be 
detected  by'straining  some  of  the  water  through  sand  and  then 
washing  the  microscopic  organisms  from  the  sand  and  examin- 
ing the  wash  water  under  the  microscope.  In  investigating 
a  prospective  water  supply  it  is  desirable  to  know  whether  it 
contains  these  troublesome  organisms  and  in  testing  the  water 
of  an  old  supply  it  is  important  to  learn  of  any  increase  in 
numbers  or  of  the  sudden  appearance  of  any  organism;  be- 
cause by  treating  the  water  with  copper  sulphate  the  objection- 
able plants  may  be  killed  and  the  disagreeable  tastes  and  odors 
prevented. 

This  examination  follows  the  so-called  Sedgwick-Rafter 
process  in  which  500  c.c.  of  the  water  is  filtered  through  sand 
from  which  the  organisms  are  washed  with  5  c.c  of  wash 
water.  This  concentrated  sample  is  examined  on  a  special 
slide  in  which  the  water  is  just  one  millimeter  deep.  A 
special  micrometer  is  used  in  the  microscope  to  mark  off  a 
field  one  millimeter  square  so  that  in  looking  through  the 
microscope  the  number  of  organisms  in  a  cubic  millimeter  of 
the  concentrated  sample  may  be  determined.  By  counting  a 
number  of  fields  a  fair  average  may  be  obtained  and  the  num- 
ber of  organisms  in  the  original  sample  may  be  computed. 
This  test  is  regularly  made  in  city  water  laboratories  because 


236  HYGIENE:     DENTAL   AND    GENERAL 

the  number  of  objectionable  organisms  varies  at  each  season 
of  the  year  and  it  is  important  to  determine  their  increase 
before  a  nuisance  is  produced. 

By  the  above  tests  the  sanitary  and  aesthetic  quality  of  a 
drinking  water  supply  may  be  accurately  determined  and  by 
the  addition  of  special  tests  for  hardness,  iron,  etc.,  its  fitness 
for  industrial  purposes  may  be  estimated.  It  is  hardly  neces- 
sary to  repeat  that  the  quality  of  a  drinking  water  cannot  be 
determined  by  its  appearance  to  the  naked  eye. 

WATER  PURIFICATION 

It  frequently  happens  that  safe  water  supplies  are  not  avail- 
able and  some  method  of  purifying  the  water  must  be  adopted. 
There  are  three  important  methods  in  general  use:  (1)  Stor- 
age, (2)  Filtration,  and  (3)  Chlorination. 

Storage. — Storage  is  the  natural  way  of  purifying  water 
and  it  is  utilized  by  man  in  securing  water  from  lakes  and 
reservoirs.  Bacteria  and  other  particles  settle  to  the  bottom 
of  standing  water  and  what  is  often  most  important  the  bac- 
teria themselves  die  of  old  age  or  are  devoured  by  other  or- 
ganisms. 

It  was  the  privilege  of  the  author  to  study  this  process  of 
natural  purification  in  a  small  stream  which  received  the 
partially  purified  sewage  effluent  from  the  city  of  Brockton, 
Massachusetts.  (Reported  as  '''Studies  on  the  Purification  of 
a  Seivage  Filter  Effluent  hy  a  Small  and  Otherwise  Unpol- 
luted Stream,"  by  Weston  and  Turner  in  Contributions  from 
the  Sanitary  Research  Laboratory  and  Sewage  Experiment 
Station,  Volume  X,  M.  I.  T.,  Cambridge,  Mass.,  1917.)  This 
study  showed  that  the  process  of  self -purification  is  largely 
biological  and  that  still  water  purifies  itself  much  more  rap- 
idly than  running  water,  because  in  the  latter  case  the  plants 
and  animals  which  assist  in  purification  processes,  are  swept 
away  while  in  still  water  they  accumulate  in  enormous  num- 
bers. 


WATER    SUPPIiY 


237 


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Yoarly   Averages  of 
NlTROCElN  AS  FheE  NH3.  AuBUMJNOlD  NM,  ,NlTR!TES. 
Ni-TRATES   AND  To-TAJ-  N   at  Stations*!  to*C)  IncluSive 

Fig.  34. — Diagram  showing  the  condition  of  the  stream  studied  at  Brockton. 
The  chart  shows  the  average  figures  obtained  from  weekly  analyses  of  the  water  at 
each  sampling  station  covering  a  full  year. 


ZSQ  hygiene  :     DENTAL    AND    GENERAL 

At  the  point  where  the  pollution  enters  the  stream  there  is 
a  sudden  increase  in  the  number  of  bacteria.  These  break 
down  the  organic  substances  of  pollution  but  they  themselves 
are  used  as  food  by  protozoa  which  are  found  in  great  numbers 
just  below  the  place  where  the  bacteria  are  most  numerous. 
The  protozoa  in  turn  are  devoured  by  small  Crustacea  and 
other  higher  animals,  which  are  suitable  food  for  fish.  The 
abundance  of  the  carbon  dioxide  and  nitrates  is  removed 


leo.ooo 


♦1      *e*3 


*6 


*5 

Sarnpl»n3   Stations 

Yearly  Avcra3«s  of 

Organisms 

Fig.    35. — Diagram    showing  the   abundance    of  microorganisms   at   the   various   sam- 
pling stations. 

by  simple  and  higher  plants  which  grow  in  such  a  quantity 
as  to  almost  clog  the  stream  and  furnish  protective  habita- 
tions for  the  millions  of  tiny  animals  which  nature  is  using 
in  the  purification  process. 

The  accompanying  diagram  shows  the  effect  upon  the 
stream  produced  by  introducing  the  sewage  effluent,  which 
came  in  between  sampling  stations  No.  1  and  No.  2.  The  other 
sampling  stations  indicated  in  the  diagram  are  approximately 


WATER   SUPPLY 


239 


^^1^ 


Fig.  36. — This  view  of  the  stream  taken  near  Sampling  Station  No.  4,  on  July 
21,  1915,  shows  how  completely  the  higher  acquatic  plants  fill  this  part  of  the 
stream  in  summer.  These  plants  strain  out  the  suspended  matter  and  prevent  the 
smaller  plants  and  animals  from  being  carried  down-stream. 


Fig.  37. — A  com  siiciii'lmy  \  m  \\  jiiiuary  26,  1916,  showing  how  differently  the 
same  region  appears  under  winter  conditions  and  high-stream  flow.  The  biological 
processes  of  purification  are  greatly  reduced.  There  is  greater  dilution  but  less 
purification. 


240  HYGIENE  :     DEXTAIj    AND    GENERAL 

the  following  distances  below  station  No.  2:  No.  (3),  980 
feet,  No.  (3a),  2000  feet,  No.  (4),  3650  feet,  No.  (5),  11,580 
feet,  No.  (6),  19,700  feet. 

The  storage  of  water  is  a  simple  method  of  purification  and 
is  inexpensive  except  where  there  may  be  a  high  cost  for  reser- 
voir construction.  Experiments  indicate  that  all  the  disease 
germs  usually  die  out  in  water  which  has  been  stored  for  a 
month.  In  reservoirs  and  in  relatively  pure  waters  the  bio- 
logical activities  are  not  as  intense  as  in  heavily  polluted  water 
and  most  of  the  bacteria  are  settled  out  on  the  bottom  or  they 
die  of  old  age  or  lack  of  food. 

Filtration. — There  are  two  types  of  filtration  for  drinking 
water,  slow  sand  filtration  and  rapid  sand  filtration.  In  the 
construction  of  a  slow  sand  filter  a  concrete  floor  is  first  laid 
down  and  drains  with  open  joints  are  laid  along  this  imper- 
vious bottom,  the  joints  being  covered  with  small  rocks.  Then 
the  whole  filter  bottom  is  covered  with  gravel  to  a  depth  of 
several  inches  and  on  top  of  the  gravel  there  is  a  layer  of 
sand  about  3  feet  in  depth.  In  cold  climates  the  whole  struc- 
ture is  placed  low  in  the  ground  and  roofed  over  with  a  con- 
crete roof  which  is  covered  with  soil.  This  is  necessary  to 
prevent  the  surface  from  freezing  up  during  the  winter 
months. 

Such  a  filter,  as  the  one  at  Washington,  D.  C,  is  made  up 
of  large  units  of  about  one  acre  each  in  area.  The  water  is 
run  onto  the  sand  to  a  depth  of  3  or  4  feet  and  filters  rapidly. 
One  acre  of  filter  surface  is  capable  of  filtering  about  three 
million  gallons  of  water  per  day.  This  process  will  remove 
,99  per  cent  of  the  bacteria  and  suspended  particles  and  will 
reduce  the  color  30  per  cent.  A  description  of  the  biological 
principles  of  the  slow  sand  filtration  will  be  found  in  the 
chapter  on  Waste  Disposal. 

The  rajyid  sand  filter  or  ''mechanical  filter"  or  "American 
Filter"  as  it  is  sometimes  called,  is  designed  to  accomplish 
the  purification  process  with  much  less  sand  area.  In  this 
process  a  coagulant  is  first  added  to  the  water  to  produce  a 


r.-^; 


WATER    SUPPLY  241 

cliemical  precipitate.  The  substances  commonly  used  are 
lime  and  alum  which  react  to  produce  aluminum  hydroxide. 
These  chemicals  are  thoroughly  mixed  with  the  water  w^hich 
is  then  passed  through  a  storage  tank  where  the  precipitate 
settles  out  carrying  down  with  it  many  of  the  bacteria  and 
much  of  tjie  dirt  suspended  in  the  water. 

From  the  top  of  this  tank  the  water  is  drawn  off  to  the  filter, 
which  in  principle  of  construction,  is  similar  to  the  slow  sand 
filter  except  that  it  is  much  smaller  in  area  and  is  enclosed  in 
a  sort  of  concrete  bin.  This  filter  is  also  supplied  with  de- 
vices which  make  it  possible  to  wash  the  surface  of  the  sand 
by  forcing  water  back  up  through  the  filter.  This  washing 
process  must  be  carried  out  frequently"  as  the  coagulant  col- 
lects on  the  top  of  the  sand  and  clogs  the  filter.  The  bac- 
terial efficiency  is  about  98  per  cent  or  99  per  cent  and  it 
operates  at  the  rate  of  125  million  gallons  of  water  per  acre 
per  day. 

Chlorination  is  the  third  important  method  of  purifying 
water.  Chlorine  is  added  either  in  the  form  of  chloride  of 
lime  or  as  chlorine  gas  liberated  from  tubes  of  liquid  chlorine. 
Various  chlorinating  devices  are  on  the  market.  In  what- 
ever form  the  chlorine  is  used  enough  must  be  added  to  kill 
the  nonspore-bearing  bacteria  and  care  must  be  taken  to  avoid 
adding  so  much  as  to  give  a  disagreeable  taste  to  the  water. 

Sometimes  complaints  are  heard  because  of  chlorine  tastes 
in  water  but  the  careful  operation  of  chlorine  plants  should 
make  it  possible  to  avoid  serious  difficulty  in  this  matter.  Not 
long  ago  I  had  occasion  to  investigate  the  water  supply  of  a 
small  town.  The  Avater  was  taken  directly  from  the  river  and 
although  chlorination  had  been  going  on  for  nearly  a  year  I 
was  informed  by  the  Chairman  of  the  Local  Board  of  Health 
and  other  citizens  that  nothing  whatever  was  being  done  to 
purify  the  water.  Apparently  there  were  no  disagreeable 
tastes  in  this  instance.  At  about  the  same  time  a  quite  dif- 
ferent incident  came  to  my  attention  at  another  town.  It  was 
generally  known  that  chlorine  was  about  to  be  used  in  the 


242  HYGIENE:     DENTAL   AND   GENERAL 

water  although  the  exact  time  when  treatment  would  begin 
was  not  known.  Complaints  of  its  disagreeable  taste  reached 
the  Health  Officer  two  days  before  any  chlorine  whatever 
was  used. 

When  the  taste  of  chlorine  does  occur  it  is  disagreeable  but 
sometimes  at  least  complaints  are  more  imaginary  than  real. 
The  amount  of  chlorine  necessary  to  disinfect  a  water  depends 
upon  the  amount  of  organic  matter  present.  Proper  methods 
of  ehlorination  render  the  water  practically  free  from  non- 
spore-bearing  bacteria. 


CHAPTER  XIII 

WASTE  DISPOSAL 

Sanitary  engineering  is  a  science  by  itself.  But  there  are 
certain  facts  and  important  principles  involved  in  waste 
disposal  which  any  person  might  well  know.  AVe  shall 
first  describe  some  of  the  principles  involved  in  the  puri- 
fication of  sewage  and  the  disposal  of  wastes,  and  then 
discuss  some  of  the  problems  in  waste  disposal  for  a  rural 
community  or  for  a  residence,  because  it  often  happens  that 
those  who  are  not  sanitary  engineers  like  to  know  about  the 
methods  applicable  at  a  camp,  a  cottage  or  an  institution  in 
which  they  may  be  interested.  By  waste  disposal  we  mean 
the  disposal  of  sewage  and  garbage. 

SEWAGE  DISPOSAL 

Sewage  is  the  material  discharged  into  the  sewers  of  a  city 
or  community  and  should  not  be  confused  with  the  word 
sewerage  which  has  to  do  with  the  sewer  pipes  themselves. 
Sewage  is  the  material  and  sewerage  the  piping  system  which 
carries  the  sewage. 

Our  consideration  will  be  directed  mainly  to  domestic  or 
household  sewage,  which  consists  chiefly  of  excreta  mixed  with 
the  sinlv  wastes,  and  other  waste  waters  going  from  the  house. 
In  city  sewage  there  are  also  street  washings  and  manufactur- 
ing wastes. 

It  is  unnecessary  to  dwell  upon  the  importance  of  proper 
sewage  disposal.  In  a  previous  chapter  we  have  seen  that 
lack  of  care  in  disposing  of  sewage  from  houses  where  there 
are  cases  of  intestinal  disease  may  result  in  serious  epidemics. 
The  organisms  of  such  intestinal  diseases  as  typhoid,  cholera, 
dysentery,  and  paratyphoid  are  discharged  in  innumerable 

243 


244  HYGIENE:     DENTAL   AND    GENERAL 

quantity  in  the  feces  of  the  patient  and  may  remain  alive 
for  many  days,  for  weeks  even.  And  wherever  drinking 
water,  milk  or  food  becomes  contaminated  with  the  excreta 
from  these  patients  there  is  a  possibility  of  spreading  the  dis- 
ease. So  that  the  first  and  most  important  problem  in  sewage 
disposal  is  to  take  such  care  of  excreta  that  there  will  be  no 
opportunity  for  spreading  infection.  But  we  must  not  only 
take  care  of  sewage  in  such  a  way  that  germs  will  be  killed 
but  also  in  such  a  way  that  it  will  not  produce  a  nuisance 
in  the  community.  The  problem  of  proper  waste  disposal 
is  not  a  simple  one. 

In  considering  disposal  we  need  to  know  the  composition 
of  sewage.  Tlie  most  important  constituent  of  domestic  sew- 
age is  the  protein  and  other  organic  material  of  the  excreta. 
Human  excrement  is  composed  largely  of  bacteria  together 
with  undigestible  products  like  cellulose  and  the  secretions  of 
the  mucous  lining  of  the  digestive  tract,  the  bile  salts  and 
special  substances  like  inorganic  compounds.  Most  of  this 
material  is  protein  and  carbohydrate,  with  a  small  amount 
of  fat. 

Direct  Disposal. — Sewage  may  be  disposed  of  either  di- 
rectly or  by  purification.  In  cities  located  on  the  seashore 
or  on  great  rivers  and  lakes  disposal  by  dilution  or  the  di- 
rect discharge  of  sewage  into  a  large  body  of  water  is  pos- 
sible. A  stream  can  purify  about  one-fiftieth  of  its  own  vol- 
ume of  raw  sewage.  In  the  woods  or  on  farms  excreta  may 
be  covered  with  soil.  But  in  the  interior  of  the  country  where 
the  population  is  becoming  more  dense  and  where  all  the 
streams  are  used  as  drinking  water  supplies  some  other  method 
of  purification  must  be  resorted  to. 

Chemical  Purification.^ — Artificial  methods  of  sewage  dis- 
posal are  by  either  chemical  or  bacteriological  purification. 
By  chemical  purification  we  mean  adding  some  chemical  like 
a  strong  alkali  or  acid  or  chlorinated  lime  to  the  sewage  in 
order  to  disinfect  it.     We  shall  cite  but  three  examples  of 


WASTE   DISPOSAL 


245 


purification  by  chemical  processes;  the  chemical  closet,  chem- 
ical precipitation  and  the  Miles  process. 

The  Chemical  Closet  in  its  simplest  form  may  be  used  in- 
side the  house.  It  consists  of  a  jar  placed  in  a  closed  box 
under  a  toilet  seat  and  contaiiiing  a  strong  solution  of  caustic 
soda  which  disinfects  and  partly  dissolves  the  excreta  which 
reach  the  liquid.  These  closets  are  nearly  free  from  odor. 
They  are  made  by  dozens  of  manufacturers  in  America  and 


Fig.   38. — A  Chemical  Closet  installed  iu  a  home  where  runiiiiig  water  is  not  avail- 
able.     (Courtesy  of  The  Dail   Steel  Products  Company,  lyansing,  Mich.) 

may  be  obtained  either  as  a  single  unit  consisting  of  a  sin- 
gle seat  or  as  a  Jai'ge  unit  consisting  ul"  several  scats  over  the 
tank.  Surli  iiistalhitious  are  jiow  used  iu  maii.v  l)o.ys'  camps 
and  in  hunting  camps. 

Chemical  Precipitation  of  the  solids  in  sewage  is  sometimes 
secured  by  the  addition  of  chemicals,  like  lime  and  alum, 


246  HYGIENE:     DENTAL   AND    GENERAL 

which  form  a  flaky  precipitate,  carrying  down  with  it  the  light 
floating  particles  in  the  sewage.  This  precipitation  takes 
place  in  a  large  chamber  or  settling  basin,  the  water  is  drawn 
off  from  the  top  and  the  remaining  solids  (sludge)  are  usually 
pressed  to  expel  as  much  water  as  possible.  The  dried  sludge 
is  hauled  out  to  sea  or  buried  on  waste  land.  It  has  small 
fertilizer  value  and  is  therefore  not  salable,  although  at  some 
purification  works  a  portion  of  the  sludge  is  hauled  away  by 
farmers  for  fertilizer  purposes. 

This  process  is  not  much  in  use  at  present  because  chemicals 
are  expensive  and  because  the  degree  of  purification  secured 
is  not  high.  The  liquid  effluent  from  this  process  is  putre- 
factive and  needs  further  treatment  unless  there  is  opportu- 
nity for  great  dilution,  the  sludge  is  produced  in  large  quan- 
tity and  there  is  no  easy  method  of  securing  its  final  disposal. 

The  so-called  Miles  Process  has  recently  been  suggested  for 
the  treatment  of  sewage  in  very  large  cities.  This  process 
disinfects  the  sewage  with  sulphurous  acid,  by  introducing 
SO2  into  a  large  tank  of  sewage  and  allowing  the  clear  and 
nearly  sterile  liquid  effluent  to  flow  on  into  the  river  or  the 
ocean  at  the  same  time  collecting  the  solid  material  and  fats 
in  sedimentation  chambers.  The  proteins  settle  out  at  the 
bottom  of  the  tank  and  may  be  used  as  fertilizer  base.  The 
fats  are  released  by  the  chemicals  and  may  be  skimmed  from 
the  top  of  the  liquid,  purified  and  sold  for  soap  grease.  This 
process  is  still  in  the  experimental  stage  but  seems  to  be 
Avorthy  of  trial  by  large  cities. 

Bacteriological  Purification.— There  are  two  widely  dif- 
ferent processes  for  the  bacteriological  purification  of  sewage, 
the  aerobic  and  the  anaerobic.  It  is  the  presence  or  absence  of 
oxygen  that  determines  which  of  these  two  processes  will  take 
place. 

.ffirobic  Processes. — The  biological  principles  of  aerobic 
purification  have  already  been  alluded  to  in  our  reference 
to  the  nitrogen  cycle  in  the  discussion  of  the  interpretations  of 
the  chemical  water  analysis.     When  enough  oxygen  is  sup- 


WASTE    DISPOSAL  247 

plied  to  sewage,  as  it  is  being  broken  down  by  the  bacteria 
contained  within  it,  much  of  the  nitrogen  is  finally  converted 
into  nitrates  through  the  various  descending  steps  of  the  nitro- 
gen cycle.  Carbon  dioxide  is  also  produced  in  large  quan- 
tities. When  the  process  is  completed  the  solid  residue  of 
the  sewage  (sludge)  has  somewhat  the  consistency  of  humus 
soil.  Practical  applications  of  this  principle  are  found  in 
ScM-age  Farming,  Intermittent  Sand  Filtration,  Rock  Fil- 
ters and  Oration. 

1.  Sewage  Farming. — It  has  long  been  known  that  it  is 
possible  to  purify  sewage  by  allowing  it  to  flow  on  to  soil 
which  is  largely  sand  or  gravel.  This  is  merely  the  utilization 
of  the  agricultural  process  of  fertilizing  land.  Near  Paris 
many  acres  of  sewage  farms  have  been  in  operation  since  1866. 
Farmers  buy  sewage  from  the  city  securing  thereby  both 
water  and  fertilizer.  Gates  and  ditches  are  built  in  such  a 
way  that  the  flow  of  sewage  may  be  directed  to  the  desired 
section  of  the  farm.  There  are  smaller  sewage  farms  in 
Europe  much  older  than  those  in  Paris. 

The  purification  of  sewage  by  this  method  is  almost  com- 
plete for  the  solids  are  left  upon  the  surface  and  the  water, 
which  soaks  through  the  soil  and  finally  makes  its  way  to  the 
streams,  lakes  or  rivers,  shows  little  trace  of  pollution.  But 
in  order  that  sewage  farming  shall  be  a  success  the  soil  must 
be  mainly  sand  or  gravel  and  free  from  clay,  peat  and  chalk. 
Moreover  a  great  deal  of  land  is  required  since  in  American 
cities  about  an  acre  of  land  is  necessary  to  treat  the  sewage 
of  100  people.  The  rate  of  filtration  on  the  sewage  farms 
near  Paris  is  12,000  gallons  per  acre  per  day.  There  are  a 
few  sewage  farms  in  California  where  soil  and  climate  are 
favorable,  but  for  the  most  part  American  cities  use  more  in- 
tensive methods  of  sewage  disposal. 

2.  Intermittent  Sand  Filtration. — Although  earlier  and 
limited  laboratory  studies  had  been  made  in  England,  the 
principle  of  tlie  purification  of  sewage  by  filtration  through 
sand  was  largely  developed  at  the  Massachusetts  Sewage  Ex- 


248 


HYGIENE:     DENTAL   AND    GENERAL 


WASTE   DISPOSAL  249 

periment  Station,  at  Lawrence,  between  1886  and  1890.  In 
these  experiments  sewage  was  filtered  through  several  feet  of 
sand  which  had  been  placed  in  large  round  wooden  tanks. 
These  experiments,  which  first  combined  biological,  chemical 
and  engineering  research  in  behalf  of  the  State  and  in  the  in- 
terest of  the  public  health,  form  an  important  and  interesting 
chapter  in  the  history  of  sanitary  progress. 

Sand  beds  as  they  are  now  constructed  are  usually  about 
one  acre  in  area  and  from  4  to  5  feet  deep.  In  making  such 
a  bed  underdrains  of  tile  with  open  joints  are  first  laid.  The 
joints  are  protected  with  rocks  and  gravel  to  prevent  the  drain 
from  becoming  clogged.  Then  coarse  sand  is  placed  over  the 
di-ain  to  a  depth  of  2  or  3  feet  and  fine  sand  is  used  for  making 
the  top  of  the  filter.  The  bed  is  flooded  with  sewage  to  a 
depth  of  a  few  inches  and  then  allowed  to  dry  after  which  a 
' '  breathing  space ' '  of  several  hours  is  allowed  before  a  second 
dose  of  sewage  is  put  on  the  bed. 

The  reason  for  this  intermittent  method  of  dosing  the  sand 
bed  becomes  apparent  upon  a  consideration  of  the  biological 
principles  involved.  It  is  found  that  as  the  bed  is  used  the 
sand  grains  near  the  surface  become  coated  with  a  gelatinous 
growth  of  the  oxidizing  bacteria  to  which  the  sewage  purifica- 
tion is  due.  This  gelatinous  coating  of  the  sand  grains  makes 
the  filter  more  tight  and  as  the  coating  becomes  heavier  with 
increased  numbers  of  bacteria  the  efficiency  of  the  filter  rap- 
idly increases.  These  are  asrobic  or  oxygen  breathing  bacteria 
and  it  is  therefore  necessary  to  let  the  filter  rest  or  ' '  breathe ' ' 
long  enough  for  oxygen  to  penetrate  into  the  bed  between  the 
times  when  the  bed  is  flooded  with  sewage. 

A  good  intermittent  sand  filter  will  remove  99  per  cent  of 
the  bacteria  of  sewage  and  effect  a  very  high  degree  of  puri- 
fication. In  fact  the  effluent  from  such  a  filter  is  almost  a 
"drijiking  Avater"  effluent.  A  filter  bed  one  acre  in  area 
will  treat  from  fifty  thousand  to  one  hundred  thousand  gal- 
hms  of  sewage  per  day.  In  other  Avords  one  acre  of  filter 
will  provide  sewage  treatment  facilities  fur  about  six  hundred 
people. 


250  HYGIENE:     DENTAL    AND    GENERAL 

3.  Sprinkling  Filters. — Sprinkling  or  percolating  filters 
treat  sewage  much  more  rapidly  than  intermittent  sand  filters. 
They  make  use  of  the  same  biological  principle  of  serobic 
bacterial  action  but  the  purification  which  such  filters  effect  is 
not  as  complete  as  in  the  case  of  the  sand  filter.  They  are 
from  6  to  8  feet  deep  and  are  composed  of  broken  stone,  coal 
or  coke  with  an  effective  size  of  from  1  to  3  inches.  This  • 
broken  stone  is  placed  upon  a  concrete  floor  which  is  properly 
drained.  The  sewage  is  thrown  onto  the  bed  through  sprin- 
kler nozzles  which  spray  the  sewage  into  the  air  in  much  the 
same  way  that  water  is  thrown  into  the  air  by  a  lawn  sprayer. 
This  allows  the  sewage  to  accumulate  oxygen  from  the  air  and 
it  is  also  continuously  in  contact  with  the  air  as  it  trickles 
over  the  rocks  of  the  porous  filter. 

Filters  of  this  type  properly  constructed  and  operated  may 
be  depended  upon  to  remove  from  70  per  cent  to  90  per  cent 
of  the  bacteria  and  to  produce  a  non-putrescible  liquid  effluent. 
This  effluent  however  contains  suspended  solids  which  are 
easily  settled  out  and  which  are  putrescible.  The  average 
rate  of  filtration  in  American  filters  of  this  type  is  about  two 
million  gallons  per  acre  per  day. 

4.  Activated  Sludge. — A  more  recent  development  in  the 
treatment  of  sewage  by  the  aerobic  process  involves  bubbling 
air  through  the  sewage  as  it  passes  through  a  deep  tank.  A 
few  inches  above  the  real  bottom  of  such  a  tank  there  is  a 
false  bottom,  which  contains  many  square  plates  of  porous 
tile.  Air  is  forced  through  these  plates  in  fine  bubbles  which 
make  their  way  through  the  sewage  to  the  top  of  the  tank.  By 
continually  forcing  air  through  the  sewage  the  small  par- 
ticles of  sludge  soon  become  "activated"  by  the  accumulation 
of  mineralizing  bacteria  so  that  the  rate  of  nitrate  formation 
becomes  exceedingly  rapid. 

A  bacterial  removal  from  80  per  cent  to  90  per  cent  is 
claimed  for  the  process,  a  liquid  effluent  of  high  quality  is  ob- 
tained find  the  sludge  is  nonputrescible  and  of  good  fertilizer 
value. 


WASTE    DISPOSAL  251 

Anaerobic  Processes. — The  aiiffirobie  decomposition  of  sew- 
age which  takes  place  whenever  sewage  is  stored  in  large 
tanks  is  quite  a  different  process.  Under  these  conditions  the 
available  oxygen  is  soon  used  up  by  the  ^robic  or  free-oxygen 
breathing  bacteria.  Such  bacteria  soon  die  for  want  of  oxy- 
gen and  there  remains  only  the  anaerobic  bacteria :  those  which 
are  able  to  wrest  their  oxygen  from  the  organic  compounds 
undergoing  septic  action.  From  such  a  process  three  gases 
are  produced  from  the  proteins,  namely,  nitrogen  gas,  am- 
monia, and  hydrogen  sulphide.  From  the  carbohydrates  some 
carbon  dioxide  and  a  greater  quantity  of  marsh  gas  are  pro- 

THE  BACTERIAL  ACTION  L\  THE  AEROBIC  AND  AN.EROHIC 
PROCESSES 

Arabic  Dccomposilion  Annrohic  Dccoiiiposition 

n,S,  CI1„  CO..  N,  Nil,. 

SEWAGE 
Nitrites  Albuminoid 

/■^^  Ammonia       ■'^;-^____^  Carboiiydrat 

^v^  /  " —  Protein 

Free  ^  Fats 


''ree  ^ 
Nitrates  Ammonia 


SliidL'e  Sludge 


duced.  This  process  results  in  the  reduction  of  the  quantity  of 
solids  but  leaves  a  residue  or  sludge  which  is  tarry  in  consis- 
tency and  appearance  and  is  further  putrescible.  The  above 
chart  contrasts  the  anterobic  and  lerobic  processes. 

1.  The  Cesspool. — A  familiar  example  of  the  anan'obie 
purification  of  scM'age  is  the  leaching  cesspool  which  is  usually 
built  like  a  well  with  sides  made  of  large  stones  between  which 
the  water  may  pass  into  the  surrounding  soil.  The  sewage 
solids  accumulate  at  the  bottom  of  this  tank  and  are  greatly 
reduced  in  volume  by  the  septic  action  of  bacteria. 

2.  The  Septic  Tank. — Sometimes  a  tank  with  tight  cement 
walls  is  used  instead  of  the  leaching  cesspool  and  here  there 


252 


HYGIENE  :     DENTAL   AND   GENERAL 


is  an  even  better  opportunity  for  anserobic  action  to  take  place. 
Here  as  in  the  old  style  cesspool  the  quantity  of  solids  is 
greatly  reduced  but  residue  must  be  occasionally  removed. 
Large  septic  tanks  are  used  in  the  purification  of  city  sewage. 


Fig.  40. — Imhoff  Tank.  The  water  flows  through  the  upper  chambers  of  the 
tank  A  and  B,  the  flow  being  reduced  by  the  baffles  G;  the  upper  chamber  is  sepa- 
rated from  the  lower  or  sludge  digestion  chamber  C,  by  the  partition  F;  the  solids 
settle  out  through  the  slot  /,  and  the  gases  escape  to  the  right  D,  being  separated 
from  the  fresh  sewage.      (Public  Ilealth  Bulletin  No.   101.) 


3.  TiJE  Two-story  Tank. — ]\Iore  recently  this  simple  t;nik 
has  been  improved  upon  and  wc  have  had  what  we  call  the 
two-story  tank  of  which  perhaijs  the  most  important  type  is 
that  known  as  the  Imhoff  Tank.  The  sewage  flows  slowly 
through  the  upper  chamber  and  tlie  solids  settle  to  the  bottom 


WASTE    DISPOSAL  253 

and  pass  tliroiigii  tlie  narrow  slot  into  the  lower  or  sludge 
digestion  chamber.  It  is  in  the  lower  chamber  that  the  septic 
process  takes  place  and  there  is  an  advantage  over  the  single 
story  tank  in  that  the  gases  produced  are  prevented  from  pass- 
ing through  the  fresh  sewage.  The  result  is  that  the  effluent 
of  such  a  tank  has  been  freed  from  solids  without  losing  its 
dissolved  oxygen  and  it  is  therefore  more  easily  purified 
further  by  filtration  or  dilution.  The  sludge  digests  for  sev- 
eral weeks  in  the  lower  chamber  and  is  finally  pumped  out, 
allowed  to  dry  and  is  disposed  of  on  waste  or  agricuHnral 
land. 

Possibilities  and  Limitations  of  Sewag-e  Purification. — 
The  above  illustrations  are  intended  only  to  further  explain 
the  principle  of  sewage  purification.  In  actual  practice  two 
or  more  of  these  processes  may  be  used  jointly  and  other  de- 
vices like  grit  chambers  to  remove  the  sand,  and  fine  or  coarse 
screens  to  remove  part  of  the  solids  may  be  added.  The  sew- 
age of  a  city  might  pass  successively  through  screens,  septic 
tanks  and  a  trickling  filter,  after  which  the  effluent  might  be 
disinfected  with  chlorine  before  being  alloAved  to  flow  into  a 
lake  or  stream.  The  sanitary  engineer  must  prescribe  a  treat- 
ment in  each  case  which  is  adapted  to  the  sewage  itself  and  to 
the  condition  and  location  of  the  city. 

A  good  example  of  purification  may  be  found  at  the  city  of 
Brockton,  Mass.  Brockton  is  an  inland  city  of  about  65,000 
population  which  is  not  located  on  or  near  any  large  lake,  or 
river.  The  sewage  is  purified  by  sprinkling  filters  and  then 
by  slow  sand  filtration,  after  which  the  effluent  is  carried 
into  a  small  brook.  The  average  daily  fiow  of  this  brook  in 
summer  is  only  a  half  million  gallons  -per  day,  but  so  com- 
pletely is  the  sewage  purified  that  two  million  gallons  of  sew- 
age effluent  are  received  daily  by  the  little  brook  without  pro- 
ducing a  nuisance.  Moreover,  studies  upon  the  self-purifica- 
tion of  this  stream  referred  to  in  a  previous  chapter  show  that 
the  final  processes  of  purification  are  carried  out  so  swiftly 


254  HYGIENE  :     DENTAL    AND   GENERAL 

by  the  innumerable  plants  and  animals  of  the  "food  cycle" 
referred  to  that  two  miles  below  the  point  where  the  sewage 
effluent  enters,  the  stream  has  regained  its  normal  appearance. 
It  is  possible  to  purify  sewage  and  discharge  the  effluent 
into  a  stream  Avhich  is  soon  to  be  used  again  as  a  city  water 
supply  provided  the  second  city  adopts  proper  methods  of 
purification  for  its  drinking  water.  But  there  is  danger  that 
we  may  go  too  far  in  this  direction.  No  one  likes  to  feel  that 
he  is  drinking  purified  sewage  even  though  the  purification 
process  is  complete  and  the  pollution  fairly  remote.  Further- 
more, in  such  a  case  there  is  the  possibility  of  a  slip  in  the 
purification  process  and  the  consequent  contamination  of  the 
drinking  water  supply.     If  such  a  process  of  purification  is 


Fig.  41. — Sewage  purification  plant  at  Atlanta,  Ga.  In  the  foreground  there 
are  grit  chambers  in  which  the  sand  is  settled  out.  The  water  then  flows  into  the 
large  Imhofif  Tanks  beyond  and  from  these  tanks  the  effluent  is  carried  to  trickling 
filters  some  of  which  are  seen  in  action.  To  the  extreme  left  a  sand  bed  for  dry- 
ing the  sludge  appears  in  indistinct  outline. 

necessary  it  is  certainly  much  better  to  have  sand  filters  be- 
tween the  scM^age  and  the  water  supply  than  to  rely  upon 
other  methods  of  purification  or  disinfection.  A  table  (see 
p.  255)  has  been  added  indicating  the  pre-war  cost  and  some 
of  the  facts  of  construction  and  operation  of  the  more  impor- 
tant methods  of  sewage  purification. 

Rural  Sanitation. — The  important  problems  of  rural  sani- 
tation, that  is,  the  disposal  of  wastes  in  rural  communities, 
cannot  be  better  presented  in  the  available  space  than  by  the 
excellent  report  of  the  Committee  on  Sewerage  and  Sewage 


WASTE   DISPOSAL 


255 


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25G  HYGIENE:     DENTAL   AND    GENERAL 

Disposal  of  the  Sanitary  Engineering  Section  of  the  American 
Public  Health  Association.  The  following  precise  and  care- 
fully prepared  report  presented  at  the  October  meeting  of  the 
Association  at  New  Orleans  in  October,  1919,  is  reproduced 
here  through  the  courtesy  of  the  Association. 

It  is  well  known  to  those  who  have  spent  much  time  in  our  rural  dis- 
tricts that  the  vast  majority  of  families  retain  in  use  the  antiquated 
privy  with  its  menace  of  typhoid  by  the  contamination,  of  wells  and 
springs,  and  through  the  agency  of  flies  j  the  possible  transfer  of  the 
hookworm,  tapeworm  and  other  parasites  by  contact  through  tlie  soil 
and  vegetable  life,  and  with  its  attendant  obnoxious  odors. 

It  is  true  that  among  the  better  class  of  farmers  these  conditions  are- 
being  ameliorated  and  in  many  cases  really  modern  and  sanitary  meth- 
ods have  superseded  the  objectionable  privy;  but  rural  communities  as 
a  whole  are  conservative  and  progress  in  such  matters  is  slow. 

For  instance,  it  was  found  upon  an  inspection  by  the  United  States 
Health  Service  in  72  towns  of  populations  varying  from  500  to  20,000 
located  in  15  representative  counties  of  13  different  states,  but  one 
was  ''free  from  grossly  insanitary  privies."  In  Comiecticut  "of  the 
15  to  20  analyses  of  wells  received  in  tliis  office  (of  the  State  Depart- 
ment of  Health)  each  week,  practically  95  per  cent  show  evidence  of 
contamination."  In  Indiana  60  per  cent  of  the  shallow  wells  have 
been  found  impure,  and  in  Wisconsin,  which  is  certainly  not  a  retro- 
grade state  in  regard  to  sanitary  matters,  it  has  been  found  that  from 
30  to  40  per  cent  of  the  water  supplies  on  farms  contain  B.  coli,  in- 
dicating contamination  by  barnyard  drainage. 

For  this  reason  the  committee  has  taken  Bural  Sanitation  as  applied 
to  the  Collection  and  Disposal  of  NigMsoil,  Sewage  and  Garbage  as  a 
lit  and  timely  subject  for  report.  A  further  reason  for  its  selection 
lies  in  the  fact  that,  while  there  is  much  valuable  literature  on  the  sub- 
ject, particularly  in  the  bulletins  of  boards  of  health,  the  information 
remains  scattered,  unrelated  and  unstandardized. 

It  is  hoped  that  by  presenting  a  few  typical  and  inexpensive  meth- 
ods to  be  followed  and  devices  to  be  recommended  for  the  disposal 
of  rural  wastes  from  a  limited  number  of  individuals  and  under  ordi- 
nary conditions,  this  report  may  serve  a  useful  purpose  as  a  guide  to 
the  householder,  physician  and  local  health  officer. 

The  object  to  be  obtained  and  the  methods  to  be  employed  may  be 
eategorieally  outlined  as  follows: 


WASTE   DISPOSAL  257 

Object 

To   collect   and   dispose    of   iiightsoil,   sewage    and   garbage    in    rural 
communities : 

(a)  Without  danger  to  health  by 

Contamination  of  the  soil; 

Contamination   of  vegetables; 

Contamination   of  water   or  ice   supplies; 

Direct  contact; 

Indirect   contact    (flies,  mosquitoes,  vermin). 

(b)  Without  the  dissemination  of  offensive  or  disagreeable  odors. 

(c)  Without  offense  to  sight  by 

Lack  of  privacy; 

Exposure   of   dejecta; 

Day  removal  of  nightsoil  near  habitations. 

(d)  Without   breeding   or   attracting   undesirable   insects   or   vermin. 

(e)  With  the  maximum  of  convenience  and  comfort. 

(f)  Without    unnecessary    expense — 

First  cost  may  often  be  reduced  by  obtaining  expert  advice. 
Operating  costs  may  be  kept  dovpn  by  providing  efficient  super- 
vision  (effect  of  frost,  repairs,  utilization  as  fertilizer). 

Methods 

1.  Disposal  of  nightsoil  or  dry  disposal 

(a)  The  straddle  trench 

(b)  The  pit  privy 
Movable   or  temporary 
Pixed  or  permanent 

(c)  The  receptacle    (pail,  tub  or  box)   privy 

(d)  The   chemical   closet 

2.  Disposal  of  sewage  or  wet  disposal 

(a)  The  cesspool.     No  outlet  provided 
Pervious 

Impei-vious 

(b)  The  tank.     Outlet  provided 
Plain  settling 

Septic 
Imhoff 
FolloTsred   by 
Dilution 

Surface  irrigation 
Subsurface  irrigation 
Sand  filtration 
Trickling  filters 
Contact  beds  and  sometimes  also  by  disinfection 


258  HYGIENE:     DENTAL    AND    GENERAL 

(c)    The  soaknge  or  absorption  i)it  for 
Urine 
Slops 

3.  Disposal  of  garbage 

(a)  By  filling  in  land 

(b)  By  burial 

(c)  By  use  as  fertilizer  on  the  land 

(d)  By  burning 

(e)  By  reduction  for  recovery  of  grease  and  tankage 

(f)  By  feeding  to  hogs 

4.  Disposal  of  manure 

(a)  By  burning 

(b)  As  fertilizer 

With  prevention  of  flies  during  storage 

With  protection  from  flies  or  direct  contact  with  excrement  provided, 
there  are  few  methods  of  disposal  in  general  use  that  may  not  be  em- 
ployed under  special  conditions  as  to  remoteness  from  habitations, 
w^ater  supplies  or  cultivated  land.  Much  depends  on  the  climate,  the 
character  of  the  soil  and  the  reliability  of  maintenance  obtainable. 
General  principles  remain  the  same  for  all,  but  the  application  may 
differ  widely  between  an  isolated  construction  camp,  a  farm,  a  military 
cantonment  and  the  outskirts  of  a  village,  and  the  cost  demanded  in 
the  last  instance  would  in  no  wise  be  justified  in  the  first. 

It  has  not  been  possible  within  the  scope  of  the  report  to  go  into 
detail  regarding  special  provisions  for  camps,  schools,  fair  grounds 
or  communities  involving  more  than  a  few  individuals  but  the  general 
principles  remain  the  same  as  for  the  individual  house. 

Dry  Disposal 

Disposal  on  the  surface  of  the  soil  is  inadmissible  from  every  point  of 
view,  inviting  transmission  of  disease  germs  by  accidental  contact, 
through  flies,  mosquitoes,  rats  or  domestic  animals,  farm  produce  and 
water  supplies.  There  is  also  the  danger  of  transmitting  hookworms 
where  these  are  indigenous  besides  being  an  offense  to  sight,  smell  and 
the  sense  of  decency. 

The  Straddle  Trench  is  the  most  primitive  form  of  sanitary  provision, 
and  is  adapted  only  to  such  situations  as  are  found  in  lumber  camps, 
with  mobile  troops,  etc.,  I'emote  from  habitations.  The  trench  is  about 
twelve  inches  in.  both  depth  and  width  and  of  the  necessary  length.  The 
earth  removed  is  banked  on  each  side,  serving  as  a  rest  for  the  feet. 
After  use  the  excreta  should  be  at  once  covered  Avith  earth  several 
inches  in  depth. 


WASTE   DISPOSAL  259 

A  iiuirc  (l('siial)lo  di'viec,  but  siutal)lo  oii1>  for  soeluded  locations  r-on- 
.sists  of  a  clicap  and  simple  Box  S0<it  wliicli  may  be  j)laced  ovit  a  jiit 
witliout  any  suporstnictnie  and  moved  as  occasion  requires.  The  liox 
slitmld  be  fly-tiglit  and  tlie  lid  self  closiiiio-,  in  ■wliich  case  the  strictly 
sanitary  requirements  may  be  met  proN'ideil  caie  is  exercised,  in  select- 
ing- the  location. 

Tlic  Pit  Privy  is  the  simplest  arrangt'ment  that  meets  the  require- 
ments of  sanitation  and  privacy.  If  improperly  built  or  located  it  is 
a  serious  menace  to  health,  especially  on  account  of  the  transmission 
of  pathogenic  bacteria  by  flies,  animals  and  water  used  for  household 
purposes.  If  permitted  to  overflow  during  storms  and  contaminate  the 
surface  of  the  ground,  the  danger  is  gi'eatly  increased.  These  objec- 
tions may  be  overcome  by  providing: 

A  pit  of  proper  depth  and  capacity. 

A  tight  superstructure  so  designed  as  to  prevent  the  passage  of  flies 
to  or  from  the  pit. 

A  floor  above  the  ground  level. 

A  door  and  lids  to  the  seats  that  close  when  not  in  use. 

Duralfle  screens  over  all  openings  for  ventilation. 

If  tlie  pit  privy  is  for  use  in  famis,  camps,  hunting  lodges,  etc.,  far 
from  other  dwellings  and  sources  of  water  supply,  the  pit  may  be  left 
pervious,  and,  when  necessary,  the  superstructure  moved  to  a  new  lo- 
cation, a  pit  for  which  has  been  prepared  in  advance. 

The  pervious  pit  should  never  be  used  in  villages  or  where  the  con- 
tamination of  Avells  or  other  Avater  supplies  is  possible.  In  that  case 
the  pit  or  vault  should  be  given  am  impervious  lining.  The  structure 
then  becomes  more  fixed  and  permanent  in  character.  By  constructing 
the  vault  in  two  compartments  they  may  be  used  alternately  for  several 
months.  While  resting  in  a  ventilated  chamber  the  contents  diminish 
in  volume  and  become  easier  and  less  offensive  to  handle,  especially  if 
a  little  dry  earth  or,  better,  lime  has  been  added  each  time  the  privy 
is  used. 

In  general,  other  wastes  than  excreta  should  be  excluded  from  the 
pits  or  vaults  or  privies.  If  the  vault  contains  much  dilute  liquid, 
cleaning  is  expensive  and  in  warm  weather  mosquitoes  may  breed.  This 
may  be  prevented  by  adding  a  cupful  of  petroleum  to  the  contents  every 
week  or  two. 

By  providing  a  removable  box  seat  the  pits  of  latrines  or  privies 
may  be  burned  out  at  least  three  times  a  week,  using  a  gallon  of  crude 
oil  to  fifteen  pounds  of  hay  or  straw.  Otherwise  it  may  be  sprayed 
with  a  mixture  of  one  pound  of  lampblack  to  two  gallons  of  kerosene  or 
one  pound  of  bone-black  to  three  gallons  of  crude  oil. 


260 


HYGIENE:     DENTAL   AND    GENERAL 


Screens  should  be  durable,  of  from  14  to  18  uieslies  per  incli.  If 
painted  light  blue  tliey  repel  flies  and  are  difficult  to  see  through  from 
the  outside. 

The  Beceptacle  Privy,  in  which  a  can,  pail,  box  or  tray  is  substituted 
for  a  pit  or  vault,  has  an  advantage  in  the  possibility  of  placing  it 
indoors  if  an  outhouse  is  not  available,  and  in  the  prompt  removal  of 
wastes  and  constant  supervision  which  are  then  essential.     On  the  other 


Fig.   42. — A  single-seated   sanitary  privy.      Front  view.      (After   Stiles.) 

hand,  for  this  very  reason,  it  is  less  fool-proof  than  the  well-built  pit 
privy  and  so  should  be  used  only  when  someone  can  be  responsible  for 
its  regular  care. 

The  receptacle  has  a  capacity  preferably  of  about  two  cubic  feet.  It 
should  be  removed  at  least  once  a  week  in  warm  weather,  or  when  about 
two-thirds  full,  and  be  replaced  by  a  clean  receptacle  with  an  inch  or 


WASTE   DISPOSAL 


261 


so  of  sawdust  or  dry  eai'th  in  the.  bottom.  It  may  be  handled  from  in- 
side or  from  the  rear  of  the  privy  house,  and,  in  order  to  prevent  the 
access  of  flies,  it  should  fit  tight  directly  under  the  seat,  to  which 
position  it  should  be  directed  by  guide  strips  nailed  to  the  floor. 

The  use  of  any  but  thin  paper  should  be  avoided  and  after  use  the 
contents  should  be  sprinkled  with  lime,  ashes  or  dry  earth  kept  in  a 
box  or  pail  convenient  for  the   purpose.     The  precautions  for  veutila- 


J''ig.  43. — Rear  and  side  view   of  privy  shown  in   Fig.   -12.      (.\fler   Stiles.) 


tion,  screening,  etc.,  and,  if  out  of  doors,  the  construction  of  the  super- 
structure are  the  same  as  for  the  pit  privy. 

To  avoid  odor  the  receptacle  should  be  washed  when  emptied  with  a 
]0  per  cent  solution  of  cresol  and  the  outside,  if  of  metal,  scoured  with 
sand  and  paraffin, 


262  HYGIENE:     DENTAL    AND    GENERAL 

In  military  camx^s  or  where  used  by  careless  persons  the  seats  should 
be  scrubbed  daily  with  soap  and  water  and  at  least  twice  a  week  with 
a  solution  of  one  and  one-half  ounces  of  cresol  in  a  gallon  of  water. 

The  necessity  of  providing  for  the  accession  of  farm  hands  during, 
the  harvesting,  berry-picking  and  canning  season  is  important  on  ac- 
count of  its  bearing  on  the  jjossible  contamination  of  food  supplies. 
For  such  situations  a  receptacle  consisting  of  a  long  trough  which  can 
be  inserted  under  several  seats  and  withdrawn  for  cleaning  may  be 
substituted  for  the  ordinary  can. 

If  the  contents  of  the  cans  become  frozen  so  as  to  render  emptying 
difficult,  they  may  be  immersed  in  warm  water  a  few  minutes,  when 
they  are  readily  emptied.  Otherwise  a  surplus  number  of  cans  should 
be  provided  so  that  when  filled  they  may  be  stored  until  thawed  out. 

The  out-door  privy  should  be  inconspicuous.  A  trellis  or  a  few  shrubs 
before  the  door  will  secure  this  end  and  improve  the  general  appearance 
of  the  place  as  well. 

T/iC  Chemical  Closet  is  a  receptacle  privy  in  which  the  contents  of 
the  receptacle  are  largely  liquefied  and  sterilized  by  a  strong  caustic 
solution,  such  as  a  solution  of  sodium  or  potassium  hydroxide. 

If  properly  designed  and  cared  for  and  with  proper  chemicals  it 
may  be  placed  in  any  convenient  place  in  the  house  or  elsewhere  and 
therefore,  need  never  be  exposed,  inaccessible  or  uncomfortable.  Dan- 
ger of  soil  pollution  or  other  means  of  disseminating  disease  is  greatly 
reduced  and  it  is  easily  ventilated  and  cleaned.  On  the  other  hand,  it 
requires  the  attention  demanded  of  any  receptacle  privy  and,  in  addi- 
tion, the  proper  selection  and  use  of  the  chemical.  Where  such  atten- 
tion is  assured,  the  chemical  closet  is  well  adapted  to  the  use  of  invalids, 
schools,  institutions  and  resorts  that  have  no  facilities  for  sewerage. 

The  final  disposal  of  nightsoil  is  quite  as  important  as  its  collection. 
It  should  not  be  accessible  to  insects,  vermin,  barnyard  fowl  or  stock, 
or  be  liable  to  come  in  contact  with  the  human  person  during  or  after 
removal.  It  should,  therefore,  never  be  placed  on  the  surface  of  the 
ground. 

Where  receptacles  arc  used  by  villages  or  cantonments  removal  should 
1)0  done  under  some  central  authority  and  during  transit  the  nightsoil 
should  be  kept  under  cover. 

If  a  sewerage  system  is  within  reach  tlie  best  plan  is  to  dump  the 
nightsoil  into  one  of  the  sewers.  Otherwise,  burial  in  the  ground  is 
usually  the  simplest  and  best  method.  This  is  sometimes  done  by  plow- 
ing a  furrow,  distributing  the  material  iu  it  and  plowing  under,  but 
as  there  is  too  great  a  likelihood  of  imperfect  covering  in  this  way 
it  is  recommended  that  this  be  done  by  hand. 


WASTE   DISPOSAL  263 

A  preferable  method  is  to  dig  a  treiieh  from  9  to  18  inches  deep  (2-i 
inches  in  winter),  place  the  nightsoil  in  this  to  a  depth  of  from  2  to  4 
inches  and  backfill  at  once  Avith  at  least  4  inches  of  earth.  The  bac- 
teria indigenous  to  the  soil  at  this  depth  Avill  effectually  dispose  of  the 
material  without  offense.  Tliis  method  should  be  carried  out  in  some 
well,  drained  sunny  field  which  will  not  l)e  xnit  under  cultivation  within 
six  months  (twelve  months  in  regions  where  the  hookworm  prevails). 
Such  a  field  should  not  drain  toward  a  well,  spring  or  other  source  of 
water  supply.  It  should  be  at  least  300  feet  therefrom  or  from  any 
dwelling.  No  hogs,  cattle  or  poultry  should  have  access  to  land  devoted 
to  this  purpose.  In  this  way  3,600  cubic  feet  of  nightsoil  may  ordi- 
narily be  disposed  of  per  acre  of  ground. 

Another  method  of  disj^osal  for  nightsoil  is  by  incineration  with  rulj- 
bish;  or  it  may  be  utilized  as  a  fertilizer,  preferably  first  allowing  it 
to  rot  for  a  year.  These  methods  cannot  be  recommended,  however,  on 
account  of  the  danger  of  odor  and  flies. 

To  deodorize  pi-ivies,  milk  of  lime  should  be  added  to  their  coutents 
once  a  week,  but  for  the  disinfection  of  nightsoil  a  solution  of  one  pound 
of  chloride  of  lime  in  five  to  eight  gallons  of  water,  or  a  3  to  5  per 
cent  solution  of  eresol,  will  be  found  more  effective,  using  from  three- 
fourths  to  one  gallon  per  cubic  foot  of  nightsoil. 

To  prevent  the  breeding  of  flies  the  nightsoil  should  be  sprinkled  with 
powdered  borax  or,  better,  a  solution  of  one  pound  of  borax  to  a  gal- 
lon of  water  for  every  10  cubic  feet  of  nightsoil,  applied  once  every  10 
days. 

No  privy  should  be  located  within  20  feet  of  a  house;  Avithin  50  feet 
of  sleeping  or  eating  quarters  in  a  camp  or  cantonment;  within  50  feet 
of  a  stream ;  or,  if  leaching  into  the  soil  is  possible,  within  200  feet 
of  any  body  of  water  that  may  be  used  for  household  purposes,  or 
upon  land  draining  directly  toward  a  well,  spring  or  stream  thus  used. 

Wet  Disposal 

The  Cesspool  is,  in  effect  a  deep  pit  privy  with  a  pervious  lining. 
If  impervious  it  is  practically  a  crude  form  of  septic  tank  and  there 
appears  no  good  reason  why  a  well-designed  tank  should  not  be  pre- 
ferred in  every  case. 

Cesspools  are  usually  from  7  to  12  or  more  feet  in  deptli  and  the 
minimum  capacity  may  be  placed  at  about  80  cubic  feet.  They  per- 
mit gross  pollution  of  the  subsoil  and  so  sliould  be  only  used  in  remote 
.regions  and  where  the  water  supply  is  brought  from  a  higher  level  and 
from  a  considerable  distance,  depending  on  the  formation.  They  should 
not  be  used  where  the  ground  water  stands  Avithin  10  feet  of  the 
surface,  or  Avhere,  as  in  limestone  regions,  natural  underground  cliannels 
may  exist. 


264  HYGIENE:     DENTAL   AND   GENERAL 

As  with  the  pit  privy,  surface  water  should  be  rigidly  excluded,  the 
structure  made  entirely  flyproof,  and  the  same  methods  should  be  ap- 
plied for  disinfection. 

The  cesspool  should  be  cleaned  when  filled  to  within  not  less  than  2 
feet  of  the  top.  This  may  be  accomplished  pneumatically  by  employing 
a  portable  "odorless  excavator"  which  conveys  the  material  to  the 
nearest  sewer  or  to  a  field  for  irrigation,  but  to  avoid  handling  large 
volumes  of  liquid  that  fail  to  leach  into  the  ground  this  may  be  per- 
mitted to  overflow  to  a  line  of  subsoil  distribution  tile  or  to  a  specially 
prepared  bed  of  gravel  or  cinders,  from  which  it  will  gradually  soak  into 
the  surrounding  soil. 

If  used  as  a  fertilizer  by  irrigating  the  land  this  should  only  be  done 
in  dry  sunny  weather,  on  pervious  land  located  at  a  distance  of  at  least 
a  quarter  of  a  mile  from  any  dwelling  and  on  which  only  trees,  shrubs, 
grain  or  root  crops  are  cultivated,  and  where  these  are  not  to  be  har- 
vested within  a  month. 

The  Septic  tank  is  the  type  of  tank  generally  to  be  recommended  for 
isolated  houses  having  a  public  water  supply  and  a  soil  favorable  for 
subsoil  irrigation  for  the  effluent.  Otherwise  resort  must  be  had  to 
some  form  of  dry  disposal. 

For  single  houses  the  capacity,  including  space  for  sludge,  should 
equal  the  volume  of  sewage  to  be  received  in  about  36  hours,  or  say  10 
cubic  feet  for  each  person. 

No  surface  or  roof  water  should  be  admitted. 

To  maintain  a  favorable  temperature  in  the  winter  the  surface  of 
the  sewage  in  the  tank  should,  if  possible  be  below  the  frost  line. 

The  tank  may  consist  of  two  chambers  or  of  a  single  chamber  with 
baffles,  and  for  small  installations  it  should  be  covered.  Hopper  bot- 
toms with  sludge  outlet  pipes  facilitate  the  collection  and  removal  of 
sludge  but  usually  add  to  the  cost. 

Inlet  and  outlet  pipes  should  terminate  from  12  to  24  inches  below 
the  surface  of  the  sewage. 

Gas  vents  should  be  provided. 

Only  thin  toilet  paper  should  be  used. 

No  disinfectant  should  be  employed,  but  a  thin  film  of  oil  may  be 
kept  on  the  surface  to  prevent  odor  and  the  breeding  of  mosquitoes. 

The  tank  should  be  cleaned  annually. 

To  promote  bacterial  activity  a  few  pints  of  sludge  from  a  neighbor- 
ing tank  or  a  little  stable  manure  should  be  placed  in  the  tank  when 
first  used. 

The  Imhoff  tanlc  is  to  be  preferred  to  the  septic  tank  for  larger  in- 
stallations, such  as  institutions,  hotels,  etc.,  as  there  is  less  liability  to 
offense  in  the  disposal  of  the  sludge.     The  period  of  retention  should 


WASTE    DISPOSAL  265 

be  from  5  to  20  hours,  depending  on  the  number  of  persons  served.     In 
other  respects  the  rules  given  for  septic  tanks  only  apply. 

The  effluent  from  either  type  of  tank  may  pass  to  a  body  of  water 
that  is  not  used  for  drinking  purposes  if  conditions  for  dilution  are 
otherwise  favorable,  but  in  most  cases  it  should  be  first  oxidized  in  some 
other  way. 

If  it  is  desired  .to  effect  a  greater  degree  of  purification  than  the 
mere  removal  of  suspended  solids,  the  tank  effluent  should  be  subjected 
to  one  of  the  f  oUomng  ' '  oxidizing ' '  processes. 

TricMing  filters  and  contact  'beds  are  adapted  in  particular  to  large 
installations  where  the  services  of  an  expert  are  required  both  in  the 
design  and  operation. 

A  special  design  suitable  for  use  by  from  6  to  120  individuals  has 
been  recently  prepared  by  the  United  States  Public  Health  Service, 
consisting  of  a  grease  trap,  ImhofE  tank,  screen,  tipping  distributer,  a 
lath  filter,  from  3%  to  6  feet  deep  having  a  volume  of  8  cubic  feet  per 
capita  and  a  secondary  Imhoff  tank.  The  whole  device  is  made  of  wood 
and  for  10  persons  is  only  13  feet  by  5  feet  10  inches  by  11  feet  0 
inches  high.  ''The  degree  of  purification  effected  is  sufficient  for  all 
purposes  except  where  the  discharge  is  directly  into  a  water  supply.  In 
such  a  case  chemical  disinfection  of  the  effluent  is  recommended  in  addi- 
tion. *  *  *  The  plant  will  operate  without  a  nuisance,  and,  with  a 
monthly  inspection  and  semiannual  or  annual  removal  of  sludge  from 
the  tanks,  will  operate  continuously  without  further  attention. ' '  (Re- 
print No.  504,  Fuhlic  Health  Eeports,  1919.)  Sufh  a  plant  should  be 
protected  from  the  weather,  particularly  in  cold  climates,  and  its  life 
would  be  much  shorter  than  if  built  of  masonry. 

Another  compact  device  consists  of  a  tank  followed  by  a  fine  copper 
screen  or  sand  filter  and  then  a  filter  of  gravel  or  pebbles  through 
which  air  is  permitted  to  rise. 

Surface  imgation,  unless  under  expert  supervision,  is  not  recom- 
mended, as  offering  too  many  opportunities  for  the  production  of  odors 
and  mosquitoes  and  for  infection  through  flies. 

Subsurface  irrigation  by  lines  of  open  joint  tile  laid  from  8  to  15 
inches  below  the  surface  may  be  the  best  method  to  employ  provided 
the  soil  is  not  Avater-soaked  or  too  impervious.  The  former  difficulty  is 
sometimes  overcome  by  embedding  the  tile  in  a  light  fill  of  sandy  soil. 
The  irrigated  area  should  be  at  least  150  feet  from  any  habitation. 

To  prevent  clogging  the  soil  the  sewage  should  pass  through  a  grease 
trap  at  the  house  and  to  promote  aeration  in  the  soil  it  should  be  de- 
livered intermittently  from  3  to  (5  times  a  day  (somewhat  less  if  the 
soil  is  dense)  by  a  siphon  contained  in  a  dosing  chamber  after  leaving 


266  HYGIENE  :     DENTAL    AND    GENERAL 

the  tank.  This  device  may  usually  be  omitted,  however,  where  the  house 
is  only  oecui^ied  during  the  summer. 

The  tile  should  generally  be  3  or  4  inches  in  diameter,  laid  Avith  a 
piece  of  tar  paper  over  the  joint  and  with  a  gradient  of  from  2  to  6 
inches  per  100  feet.  The  length  dej)ends  ui^on  the  volume  of  sewage 
and  the  character  of  the  soil,  varying  from  50  to  100  feet  for  an  ordinary 
family.  Where  more  than  100  feet  is  required  in  all  it  is  generally  de- 
sirable to  lay  tAvo  or  more  lines  of  tile.  The  arrangement  may  vary 
with  the  topography  but  parallel  lines  should  be  more  than  6,  and  pref- 
erably 10  feet  apart.  Unless  the  soil  is  quite  open  the  irrigated  area 
may  best  be  operated  in  two  units,  dosed  alternately.  If  the  land  is 
cropped  this  should  be  limited  to  grains,  fodder  croj)s  and  fruit  trees. 

Owing  to  the  difficulty  of  securing  uniform  distribution  of  the  sewage 
by  reason  of  the  variations  in  the  permeability  of  subsoil  or  improper 
gradients  or  joints  in  the  lines  of  tile,  and,  further,  owing  to  the  difficulty 
in  securing  any  effective  drainage  when  the  soil  is  saturated  by  storms, 
there  is  a  measure  of  uncertainty  in  obtaining  uniformly  satisfactory 
results  wdth  this  method  of  disposal  j  so  that,  unless  the  conditioiis  are 
favorable  and  oilier  satisfactory  methods  are  not  feasible,  subsurface 
irngation  is  not  recommended. 

Sand  filtration  may  be  used  for  tank  effluents  where  more  than  25  per- 
sons are  served  and  where  the  land  is  suitable.  For  this  number  of 
persons  an  area  of  about  1,500  square  feet  of  bed  is  required.  The 
filters  require  careful  design  and  maiiitenance.  Cropping  is  usually 
undesirable.  Dosing  should  be  intermittent  and  applied  in  rotation  to 
a  depth,  of  from  3  to  6  inches  to  two  or  more  beds.  In  winter  the 
beds  should  be  furrowed  to  prevent  freezing. 

Sludge  disposal.  Sludge  from  tanks  should  be  dried  on  porous  soil 
or  on  specially  prepared  beds.  It  should  be  placed  in  layers  of  from 
4  to  10  inches  in  thickness — the  thinner  the  better — until  sufficiently 
dry  to  be  spaded,  when  it  can  be  buried,  plowed  under  or  used  as  fer- 
tilizer. Well  digested  Imhoff  sludge  may  be  used  to  fill  in  land. 
Sludge  from  secondary  tanks,*  being  difficult  to  dewater,  should  be 
placed  on  specially  prepared  beds  to  a  depth  of  from  2  to  4  inches. 

Otherwise,  sludge  may  bo  drawn  off  into  furrows  and  covered  over. 

Fly  breeding  may  be  prevented  by  applying  a  solution  of  borax  as 
in  the  case  of  nightsoil. 

To  prevent  odor,  sludge  may  be  covered  Avith  a  thin  layer  of  car- 
bonate of  lime  or  "land  plaster." 

The  soalcage  pit  is  useful  for  the  disposal  of  kitchen  slops  and  urine 
Avhere  the  water-carriage  system  is  not  availa])le. 


•Tliose   taking  the    effluent   from   filters. 


WASTE   DISPOSAL  267 

Slox^s  may  be  spread  over  the  surface  of  the  ground  in  out-of-the-way 
locations  provided  the  soil  is  porous  and  no  standing  water  remains. 
Otherwise,  a  pit  about  three  feet  deep  filled  with  broken  stone,  gi-avel, 
sand  or  clinkers  may  be  prepared  to  which  the  slop  Avater  is  discharged 
after  the  removal  of  eoar.-e  solids  by  a  strainer  and  the  grease  by  a  trap. 
The  bed  may  be  covered  with  a  foot  or  so  of  earth  to  bring  the  top  to 
the  ground  -level  and  prevent  access  to  insects. 

For  large  volumes  a  tank  and  dosing  siphon  may  be  employed  with 
advantage,  and  a  system  of  suljsoil  tile  substituted  for  the  soakage  pit. 

Where  many  persons  are  to  be  provided  for,  as  in  schools,  hotels 
and  in  the  latrines  of  army  camps,  urinals  should  be  installed,  but  for 
private  dwellings  a  hinged  seat  that  can  be  lifted  is  a  simpler  and 
suitable  arrangement. 

Urinals  should  be  flushed  with  at  least  a  gallon  of  water  daily,  and 
it  is  desirable  that  they  be  automatically  fed  with  cresol  or  some  other 
deodorant.  The  liquid  can  then  be  led  to  a  soakage  pit  similar  to 
that  provided  for  slops. 

Another  plan  suitable  for  camps  is  to  build  one  or  more  vertical 
funnels  into  the  stone  filling  of  the  pit  to  serve  as  urinals. 

Such  a  pit  may  be  about  3  feet  to  6  feet  square  with  24  inches  depth 
of  broken  stone  or  other  pervious  material  on  the  bottom,  depending 
on  the  material  and  the  number  of  persons  served.  Large  installations 
should  consist  of  several  such  units. 

If  preferred,  a  larger  unit,  4  feet  by  12  feet  by  4  feet  deep,  adequate 
for  100  men,  may  be  substituted  for  the  one  described. 

For  emergency  use  a  cone  of  6-mesh  wire  18  inches  in  diameter  at 
the  upper  end,  24  inches  long  and  filled  w-ith  sawdust  will  serve  with- 
out a  pit  for  6  or  7  men. 

Disposal  of  Garhage 

Garliage  should  be  collected  without  admixture  of  ashes  or  other 
material  in  metal  cans  having  tight  covers,  with  one  always  available 
■\\hilc  the  others  arc  being  emptied.  The  cans  should  be  scalded  with 
hot  water  after  emptying. 

(iarbage  is  sometimes  used  to  fill  in  waste  land,  but  foi  obxious 
reasons  tliis  is  not  to  be  appro\ed. 

Garbage  from  households  may  be  satisfactorily  disposed  of  by 
burial  following  the  rules  laid  down  for  nightsoil.  Sometimes  it  is 
plowed  under  as  a  fertilizer,  but  although  it  has  some  value  in  this 
respect,  the  probability  of  odors  ordinarily  excludes  this  as  a  sanitary 
procedure.  Where  odors  from  garbage  do  occur  tlic  latter  should  l)e 
sprinkled  witli  quicklime. 


268 


HYGIENE:     DENTAL   AND   GENERAL 


If  without  too  large  a  proportion  of  moist  vegetable  matter  a  mod- 
crate  amount  can  be  safely  consumed  in  the  kitchen  range,  although 
at  the  risk  of  odor;  while  if  the  quantity  is  sufficient,  as  in  a  con- 
struction camp  or  a  military  cantonment,  a  small  but  well  designed  in- 
cinerator will   eliminate   much   of   this   objection. 

Burial  in  summer  and  incineration  in  winter,  when  the  ground  is 
frozen  and  the  garbage  is  less  moist,  will  often  be  found  advisable. 

For  camps  the  ''Woodruff  Pit"  has  been  found  a  satisfactory  do- 
vice.     This   consists   of   an   excavation   in    the   ground   from   10   to   13 


J-'ig.    44.--    (  hil. 


(Aniol.!    I\|i(l, 


((■ar'lncr.^) 


feet  in  diameter  and  4.  feet  deep,  lined  witli  fieldstone.  A  conical  pile 
of  stone  or  a  cone  of  brick  with  open  joints  is  built  in  the  center 
around  a  chimney  of  two  or  more  lengths  of  sewer  or  stovepipe.  Gar- 
bage and  nightsoil  placed  on  a  fire  built  in  the  pit  will  usually  be 
readily  consumed;  but  if,  on  account  of  wet  weather  or  very  moist 
garbage,  a  more  rapid  combustion  is  desired,  this  may  be  had  by  pour- 
ing on  a  little  kerosene  oil.  Care  should  be  taken  to  prevent  dissemi- 
nation of  papers,  etc.,  by  the  wind, 


WASTE  DISPOSAL  269 

Another  arrangement  consists  of  a  pit  5  by  2%  feet  in  plan  with 
tlie  bottom  sloping  from  a  depth  of  6  inches  at  one  end  to  12  inhces 
at  the  other.  The  trench  is  filled  with  fieldstone  or,  if  these  are  not 
available,  A\'ith  tin  cans,  the  excavated  material  is  banked  up  on  the 
sides  and  a  fire  built  on  top.  After  the  stones  arc  thoroughly  heated 
any  liquid  wastes  are  poured  in  the  trench  at  the  shallow  end  of  the 
I)it,  in  which  they  arc  evaporated,  and  the  solid  material  placed  on  top 
where  it  first  dries  out  and  then  burns,  up. 

A  certain  amount  of  odor  will  probably  be  inevitable  with  incinera- 
tion, but  with  competent  operation  this  need  not  be  serious  in  the  case 
of  camps. 

As  garbage  contains  a  considerable  amount  of  grease  which  can  be 
recovered  by  percolation  with  some  solvent,  leaving  a  tankage  with  some 
value  as  a  fertilizer  base,  this  may  prove  a  wise  method  of  disposal 
v/here  collection  can  be  made  from  a  considerable  population;  but  as 
the  plant  required  is  rather  elaborate,  this  process  can  seldom  be  availed 
of  except  for  large  cities.  The  demand  for  grease  and  fertilizer  has 
increased  so  during  the  war,  however,  their  recovery  should  be  considered 
in  connection  vsdth  army  'camps  and  cantonments. 

Probably  the  most  economical  method  for  the  farmer  and  for  towns 
of  moderate  size  is  in  feeding  to  hogs,  due  care  being  taken  to  maintain 
cleanly  conditions  about  the  pens.  The  garbage  should  not  be  kept  more 
than  48  hours  in  any  case  before  feeding.  On  account  of  the  possible 
nuisance  from  smells  and  flies  the  pens  should  be  located,  if  possible, 
at  least  a  quarter  of  a  mile  from  dwellings. 

Disposal  of  Manure 

The  manure  pile  is  a  most  prolific  source  of  flies,  which  find  in  it  a 
favorable  environment  for  breeding.  As  it  takes  about  two  weeks  for 
the  larvae  to  develop,  these  should  always  be  destroyed  if  the  manure  is 
to  be  kept  for  a  longer  period  except  in  cold  weather. 

Fifty  horses  will  produce  a  cartload  of  manure  a  day.  Fly  breeding 
may  be  prevented  by  an  application  of  borax,  using  not  over  one  pound 
to  16  cubic  feet  of  manure  if  the  latter  is  to  be  used  as  a  fertilizer,  but 
a  better  plan  is  to  sprinkle  with  a  solution  of  two  pounds  of  copperas 
per  gallon  of  water,  or  with  a  solution  of  hellebore  mixed  in  the  pro- 
portion of  one  pound  to  20  gallons  of  water  and  applied  at  the  rate  of  a 
gallon  of  the  solution  to  each  cubic  foot  of  manure.  By  consolidating 
the  exposed  surface  of  the  manure  by  battening  with  a  spade  it  will  pre- 
vent to  a  considerable  extent  the  breeding  of  flies.  The  heat  generated 
just  below  the  surface  by  decomposition  is  then  such  that  the  larvae  are 
largely  destroyed. 


270  HYGIENE  :     DENTAL    AND    GENERAL 

Tlic  most  natural  use  for  manure  is  as  a  fertilizer,  but  where  tliis 
is  impracticable  it  may  be  piled  in  windrows  about  two  feet  liigh,  sat- 
urated with  oil  and  burned. 

Of  the  safeguards  against  disease  in  our  rural  communities  those  re- 
lating to  the  protection  of  water  supplies  and  to  the  transfer  of  disease 
germs  by  flies  are  by  far  the  most  important;  so  that,  whatever  method 
of  disposal  is  adajotcd  to  a  given  situation  it  should  be  such  that  vo 
cxcretal  onatter  can  fiyid  its  way,  either  hy  'percolation  tlirougli  the  soil 
or  by  surface  loash  dxiring  storms,  to  wells  or  streams  iised  for  drinlciiig 
purposes,  and  that  all  such  excretal  matter  slwAl  he  so  protected  hy 
screening  or  otherivise  that  flies  cannot  find  access  thereto. 

In  this  connection  it  may  be  well  to  point  out  that  when  the  polluting 
material  lies  at  a  higher  elevation  than  the  water  surface  in  a  neigh- 
boring well  there  is  always  the  tendency  of  contamination  of  the  well; 
but  where  the  source  of  pollution  lies  permanently  at  a  lower  elevation 
contamination  of  the  well  will  not  occur. 

During  the  preparation  of  this  report  the  committee  has  addressed 
inquiries  regarding  the  subject  treated  to  the  health  authority  of  each 
state  as  well  as  to  others  and  has  received  in  return  a  large  number 
of  bulletins,  reports  and  prints  containing  information  of  great  value 
tliat  has  been  freely  drawn  upon  and  for  which  the  committee  desires 
to  express  its  hearty  appreciation  and  thanks. 

EespectfuUy  submitted, 

Kenneth  Allen,  Chairman. 
Frank  A.  Barbour, 
George  S.  Webster, 
T.  Chalkley  Hatton, 
Langdon  Pearse, 
Committee  on  Setoerage  and  Sewage  Disposal,  Sanitary  Section  Ameri- 
can PiMic  Health  Association. 

Bibliograpliy 

Manure  Disposal  as  a  Factor  in  the   Control   of  Parasitic  Diseases   of 

Live  Stock.     Jour.  Am.  Veterinary  Medical  Assn.,  Vol.  LI,  1917. 
Eules   and   Regulations,   Arkansas    State    Board   Health,   Pertaining   to 

Disposal  of  Human  Excreta  and  Disposal  of  Dead  Animals.     Aug., 

191.3. 
Sewage  Disposal  for  Isolated  Eesidenees.     Bui.  No.  8,  California  State 

Board  Health,  1918. 
Act   to   Regulate   the  Disposal   of   Certain   Refuse.     Approved   Jan.    2.j, 

1898.     Rep.  Health  Officer,  District  of  Columbia. 
School  Sanitation.     Florida  Health  Notes.     Florida  State  Board  Health, 

Jan.,  1918.     Public  Health  Legislation,  Florida  State  Board  Health, 

July,  1915. 


WASTE   DISPOSAL  271 

Disposal  of  Sewage  for  Country  Houses,  Small  Institutions  anil  Country 

Clubs.     Illinois  Health  News,  Aug.,  1916. 
Sanitary    Privies.     Bureau    of    Sanitary    Engineering.     Illinois    Health 

News,  May,  1917. 
Kules  and  Eegulations,  Iowa  State  Board  Health.     Supplement  to  Iowa 

Health  Bulletin,  1917. 
Methods  of  Sanitary  Disposal  of  Sewage  without  Seweis.     Health  Cir- 
cular No.  2,  Indiana  State  Board  Health,  1915. 
Amendments  to  the  Sanitary  Code  of  Louisiana  from  1911  to  Dec.  18, 

1915. 
Sanitary  Privy  for  Eural  Districts.     Louisiana  State  Board  Health,  June, 

1918. 
Sewage  Disposal  for  Country  Houses.     Quarterly  Bui.  Louisiana   State 

Board  Health,  May,  1913. 
Hygiene  of  Eural,   Suburban   and   Summer   Homes.     Circular   No.   100, 

Maine  State  Board  Health. 
A  Sanitary  Privy.     Maryland  State  Board  Health. 
Typhoid    Fever.     How    It    May    Be    Avoided.     Maryland    State    Board 

Health. 
The  Sanitary  Privy.     Eng'g  Bui.  No.  8,  Michigan  State  Board  Health, 

Feb.,  1918. 
Sewage  Disposal  for  Single  Houses  and  Small  Institutions.     Eng'g  Bui. 

No.  2,  Michigan  State  Board  Health,  Sept.,  1916. 
The  Chemical  Closet,  Eng'g  Bui.  No.  5,  Michigan  State  Board  Health, 

Oct.,  1916. 
State  Health  Laws  and  Eegulations,  ^Minnesota  State  Board  Health,  July 

16,  1917. 
Water  and  Sewerage  Systems  for  Public  School  Buildings.     Minnesota 

State  Board  Health,  Jan.,  1917. 
The  Sanitary  Privy.     Minnesota  State  Board  Health,  May,  1916. 
The  Disposal  of  Human  Excreta  and  Sewage  of  the  Country  House.    New 

York  State  Department  Health. 
Sanitary  Privies  and  How  to  Build  Them.     Spec.  Bui.  No.  7,  North  Car- 
olina State  Board  Health,  Mar.,  1917. 
Sewage  Disposal  for  Country  Schools  in  Ohio.     Ohio  Public  Health  Jour- 
nal, Aug.,  1916. 
Sewage  Disposal  for  Eesidences.     Ohio  Public  Health  Journal,  Sept. -Oct., 

1916. 
Public  Health  Laws  of  Oklahoma.     Spec.  Bui.  No.   101.  Oklahoma  De- 
partment Public  Health,  Nov.,  1917. 
Sewage  Disposal.     Circular  No.  39,  Dept.  Provincial  Sec'y  of  Ontario. 

Thirty-fourth  Eep.  Provincial  Board  of  Health  of  Ontario. 
The  Dangerous  Unsanitary  Dry  Closet.     Texas  Council  of  Defence. 


272  HYGIENE:     DENTAL   AND    GENERAL 

Home  Sanitation.     Bui.     Texas  State  Board  Health. 

Standards   of   the   Dej)artment   of   Health   and   Sanitation.     Emergency 
Fleet  Corporation.     1918. 

Transmission  of  Disease   by  Flies.       Supplement   No.   9,   U.    S.   Public 
Health  Reports,  1916. 

Flies  as   Carriers  of  Lamblia  Spores.     Eepriut  154,  Public  Health  Re- 
ports, 1913. 

Soil  Pollution.     Reprint  127,  Public  Health  Reports,  1913. 

Sewage  Disinfection.     Reprint   247,  Public  Health  Reports,   1915. 

Information    of    the    Current    Prevalence    of    Disease.      Public    Health 
Reports,    1918. 

Chemical  Closets.     Reprint  404,  Public  Health  Reports,  1917. 

New  Design  for  a  Sanitary  Pail.     Reprint  138,  Public  Health  Reports, 
1913. 

The  Sanitary  Privy.     U.  S.  Public  Health  Bui.  No.  37,  1914. 

Safe  Disposal  of  Human  Excreta  at  Unsewered  Homes.       U.  S.  Public 
Health  Bui.  No.  68,  1915. 

A  Sanitary  Privy  for  Unsewered  To\Yns  and  Villages.       U.   S.  Public 
Health  Bui.  No.  89,  1917. 

Fly   Traps  and  their  Operation.     Farmers'  Bui.   No.   734,  II.   S.   Dept. 
Agric,  1916, 

The  Sanitary  Privy.     Virginia  Health  Bui.,  Dec.  15,  1912. 

The  Pit  Privy.     Virginia  Health  Bui.,  Aug.  15,  1915. 

Rules  and  Regulations  for  Protection  of  Public  Health.     Virginia  Pub- 
lic Health  Bui.,  July,  1916. 

Sanitary  Protection  of  the  Home.     Virginia  Public  Health  Bui.,  March, 
1917. 

Rural   Sanitation,     Washington   State  Board  of   Health,   1916. 

School  Privies,     BuL     Wisconsin  State  Board  Health,  Jan.-Mar.,  1918. 

Residential  Sewage  Disposal.  Bui.  Wisconsin  State  Board  Health,  Oct.- 
Dec,  1917. 

Proceedings  Third  Biennial  Conference  of  Health  Officers  of  Wisconsin. 
1916. 

Code  for  Rural  School  Privies.     Wisconsin  State  Board  Health,  1918. 

Twenty-sixth  Report  State  Board  Health  of  Wisconsin. 

Sanitation  of  Rural  Workmen 's  Areas.     Reprint  487,  U.  S.  Public  Health 
Reports,  1918. 

Rockefeller   Foundation.     International   Health   Board,|  4th  Annual  Re- 
port, Dec.  31,  1917. 

Sewage  Treatment  for  Village  and  Rural  Homes.     Bui.  41,  Engineering 
Experiment  Station,  Iowa  State  College  of  Agriculture. 

Rural  Home  Sanitation.     Pub.  No.  2,  Texas  State  Board  Health. 


WASTE   DISPOSAL  273 

The  Treatment  of  Sewage  from  Single  Houses  and  Small  Communities. 

Eeprint  504,  Public  Health  Eeports,  U.  S.  Public  Health  Service. 
Camp  Sanitation.     Jour.  Franklin  Inst.,  June,  1918. 
Field  Sanitation.     C.  G.  Moore  and  E.  A.  Cooper. 
Orders  Eelative  to  the  Operation  and  Maintenance  of  Water  and  Sewage 

Works   at   Armv  Camps   and   Cantonments.     Construction   Division, 

U.  S.  A. 
Sanitation  in  War.     Maj.  P.  S.  Lelean. 
Prevention  of  Disease  and  Care  of  the  Sick.     U.  S.  Public  Health  Service. 


CHAPTER  XIV 

SCHOOL  HYGIENE 

The  Problem,. — The  duties  of  organized  government  in 
School  Hygiene  are  extensive  and  important.  The  state  by 
its  excellent  compulsory  school  attendance  law  places  almost 
a  third  of  our  total  population  in  this  ''factory"  for  the  de- 
velopment of  the  mind.  Dr.  Osier  has  said  that  most  of  the 
diseases  which  cause  death  in  middle  life  are  developed  from 
conditions  begun  in  childhood.  America  has  been  behind  the 
European  countries  in  developing  the  subject  of  School  Hy- 
giene but  the  examination  of  ten  million  of  our  population 
in  the  selective  draft  brought  home  forcibly  to  the  American 
people  the  fact  that  one-third  to  one-half  of  our  young  men 
are  unfit  for  full  military  service  because  of  physical  defects 
many  of  which  are  correctable.  We  have  begun  to  face  the 
problem  of  properly  caring  for  our  school  children  in  a  serious 
and  right-minded  fashion  realizing  the  vast  amount  of  work 
which  lies  before  us. 

The  following  discussion  of  this  broad  and  complex  sub- 
ject is  intended  to  give  only  the  outline  and  general  nature 
of  the  problem  with  special  emphasis  upon  those  phases  of  the 
work  in  which  the  dentist  is  likely  to  take  part.  Nor  shall 
M^e  attempt  to  define  the  relative  responsibilities  of  the  edu- 
cational and  health  agencies  of  the  government  in  this  field. 
Obviously  there  is  both  an  educational  and  a  health  aspect  to 
the  problem.  The  personnel  of  both  departments  is  necessary 
and  a  division  of  the  details  of  administration  must,  for  the 
present  at  least,  frequently  depend  upon  local  conditions. 
The  question  of  who  does  the  work  is  not  so  important  as  that 
the  work  is  done  and  done  properly. 

274 


SCHOOL    HYGIENE  275 

Special  Groups  of  Defectives.^ — School  authorities  keenly 
realize  the  difficulties  iu  educational  progress  caused  by  the 
special  jDhysical,  mental  and  temperamental  disabilities  from 
which  certain  children  suffer.  These  children  have  defects 
which  make  it  desirable  and  in  some  cases  imperative,  both 
for  their  own  good  and  in  justice  to  the  other  pupils,  that 
their  education  be  conducted  in  special  classes  apart  from  the 
public  school.  Such  defectives  have  been  divided  into  the 
following  eight  ela.s.ses:  (Crowlej-'s  Hygiene  of  School  Life.) 

1.  NeiTOus  cliildren. 

2.  Backward  children,  consisting  of  two  main  sulxtivisions : 

(a)  Dull  children  whose  backwardness  is  due  t,o  some  accidental 

cause. 

(b)  Dull   children  with   inherent   diminished   capacity   for   book 

learning. 

3.  Mentally  defective  children : 

(a)  Feeble-minded. 

(b)  Imbeciles  and  idiots. 

4.  Children  with  defective  vision  or  blindness. 

0.  Children  with  defective  hearing,  deafness  or  deaf  mutism. 

6.  Physically  defective   children,  including   cripples. 

7.  Epileptic  children. 

8.  Children   suffering   from    a   combination    of    physical    and   mental 

defects,  e.  g.,  the  blind  idiot,  the  feeble-minded  deaf  child. 

Obviously,  the  education  of  these  children  is  a  health  prob- 
lem as  well  as  an  educational  problem,  and  medical  service 
is  necessary  in  handling  the  problem  of  special  classes.  How- 
ever, we  must  leave  these  specialized  problems  and  confine 
our  attention  to  the  hygiene  of  the  public  schools. 

The  Scope  of  School  Hygiene. — The  activities  included  in 
school  hygiene  naturally  fall  into  three  groups : 

1.  Health  supervision  or  the  care  of  the  physical  well-being 

of  the  child. 

2.  Instruction  in  Hygiene  or  the  education  of  the  child  in 

matters  of  health. 

3.  Proper  sanitation  of  school  buildings  and  grounds,  the 

preparation  of  proper  conditions  for  study,  and  the 
conduct  of  school  work  under  hvgienic  conditions. 


276  HYGIENE:     DENTAL   AND   GENERAI; 

1.  HEALTH  CONTROL 

The  following  table  presents  the  scope  of  the  work  of  the 
first  group  in  more  detail: 

1.  Medical  or  health  supervision. 

(1)  Regular,  periodical,  physical  examination  of  children. 

(2)  Correcting  physical  defects,  eye,  ear,  nose,  throat, 
posture  and  nutrition. 

(3)  Checking  incipient  maladies. 

(4)  Correcting  unhygienic  habits  of  living  with  follow- 
up  work  at  home. 

(5)'  Dental  examination,  prophylaxis  and  repair. 

(a)  Cleaning  teeth. 

(b)  Filling  six  j^ear  molars. 

(c)  Teaching  oral  prophylaxis. 

(6)'  Prevention  of  Communicable  Diseases. 

Personnel. — Four  types  of  specially  trained  people  are 
necessary  for  the  administration  of  the  medical  side  of  school 
inspection,  the  physician,  the  school  nurse,  the  dentist  and  the 
dental  hygienist. 

The  physician  must  be  a  capable  diagnostician  with  a  fond- 
ness for  the  type  of  work  and  with  a  public  health  point  of 
view. 

The  school  nurse  has  a  variety  of  duties  in  assisting  the 
doctor  in  the  routine  of  medical  inspection,  visiting  homes  and 
interviewing  parents,  visiting  schools  and  examining  children 
for  infectious  diseases,  assisting  in  treatment  at  the  school 
clinic  and  occasionally  giving  instruction  in  hygiene  to  the 
pupils.  It  is  therefore,  highly  important  that  she  have  the 
ability  of  making  the  proper  contact  with  pupils  and  parents, 
as  well  as  the  ability  to  detect  communicable  disease  and  assist 
the  physician.  If  she  is  to  instruct  in  the  school  she  should 
know  something  about  teaching  as  well  as  nursing  because 
they  are  two  distinct  professions.  It  no  more  follows  that  a 
nurse  can  teach  than  that  a  teacher  can  nurse.     The  nurse  is 


SCHOOL    HYGIENE  277 

the  point  of  contact  between  the  family,  the  child  and  the 
school  medical  authorities  and  upon  her  common  sense  and 
practical  work  often  depends  the  success  of  the  plan.  Her 
failure  to  secure  the  cooperation  of  the  parents  in  having  the 
bodily  defects  of  the  child  corrected  and  in  maintaining  bet- 
ter home  conditions  means  a  failure  to  secure  a  practical  re- 
sult of  health  improvement.  The  woman  who  can  appreciate 
the  problems  of  the  homes  she  visits  adds  something  to  the 
value  of  her  work  which  detailed  scientific  knowledge  cannot 
supply. 

The  work  of  the  dentist  may  be  orthodontia,  repair  work 
or  prophylaxis  but  it  is  work  at  the  chair  and  not  widely 
different  from  routine  practice. 

The  dental  hygienist  stands  to  the  dentist  in  much  the  same 
relation  as  does  the  nurse  to  the  physician.  She  must  work 
with  the  children  and  perhaps  in  some  instances  with  the 
parents.  She  examines  the  teeth  and  fills  out  a  record  card, 
prepares  the  patient  for  the  dentist  and  cleans  the  teeth. 

Physical  Examination. — Dr.  Crowley,  of  England,  who  has 
examined  many  hundred  children  gives  the  following  figures 
indicating  the  proportion  of  children  having  diseases  and  com- 
mon defects  requiring  treatment  among  elementary  school 
children : 

Defects  of  vision  10%;  defects  of  hearing  5%;  ear  diseases  3%; 
marked  decay  of  the  teeth  50%;  (some  decay  80-90%);  Tuberculosis 
2%;  heart  disease  1%;  malnutrition  10%;  ringAvorm  1%. 

The  physical  examination  of  the  child,  however,  is  even 
broader  than  this  list  of  defects  and  should  include  a  study 
of  cleanliness,  nutrition,  height  and  weight,  heredity  and  en- 
vironment, and  an  examination  for  squint,  external  eye  dis- 
ease, defective  hearing,  adenoids,  ear  discharges,  enlarged 
glands,  defective  teeth,  acute  rheumatism,  chorea,  heart  dis- 
ease, lung  disease,  bronchitis,  venereal  disease,  rickets,  ane- 
mia, headache,  diseases  of  the  skin,  and  deformities.  The  fol- 
lowing card  is  one  devised  by  the  U.  S.  Public  Health  Service 
for  recording  the  results  of  physical  examination. 


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280  HYGIENE:     DENTAL   AND   GENERAL 

This  form  is  more  elaborate  than  many  communities  are  in 
a  position  to  use.  In  any  case  the  record  card  should  always 
be  of  suitable  size  for  filing  and  should  be  made  a  permanent 
record  so  that  the  health  progress  of  the  child  may  be  ascer- 
tained at  any  time. 

Treatment. — The  defects  having  been  discovered,  treat- 
ment must  be  secured.  A  blank  somewhat  after  the  follow- 
ing form  may  be  sent  to  the  parent. 


Office  Medical  Inspector  of  Schools 


Parent  or  Guardian  Address 

A  recent  physical  inspection  of ' 

Name  of  child 

attending  the   indicates  the  following 

Name  of  school 
abnormal  conditions: 

You  are  advised  to  take   to  your 

Name  of  child 
family  physician,   dentist,   oculist,   or  to  a  dispensary  for   advice 
and  treatment. 


Medical  Inspector. 


The  examination  should  be  made  at  the  school  and  the  clin- 
ical work  may  be  done  either  at  the  school  or  at  some  building 
of  the  Health  Department.  This  work  requires  special  con- 
veniences and  equipment.  The  chart  on  p.  281  shows  the 
floor  plan  and  arrangement  of  the  medical  inspector's  room 
in  general  use  in  New  York  Cit}'. 

These  quarters  should  be  centrally  located,  preferably  on 
the  ground  floor,  and  should  have  the  essentials  of  a  waiting 
room,  proper  lighting,  an  electrically  lighted  chart  and  dis- 
tance of  20  or  at  least  15  feet  for  eye  examination,  a  lava- 
tory and  table  with  the  necessary  filing  cabinets  for  records. 
The  diagram  shows  a  convenient  arrangement  by  which  the 
waiting  room  space  may  be  used  in  eye  examinations  so  that  a 
room  12  by  20  feet  is  made  sufficient.  In  cases  where  the 
room  is  not  in  constant  use  it  may  be  used  on  alternate  days 


SCHOOL    HYGIENE 


281 


as  a  clinic.  In  this  ease  the  room  should  be  somewhat  larger 
and  might  contain  as  a  complete  equipment:  a  desk,  ward- 
robe, medicine  cabinet,  two  chairs,  couch,  lavatory,  scales 
Avith  measuring  rod,  electrically  lighted  vision  chart,  portable 
screen  and  a  filing  cabinet  with  the  medical  and  surgical  sup- 
plies in  most  common  use  such  as  cotton,  gauze,  bandages 
(1  and  2  inch),  boracic  acid,  green  soap,  collodion,  tincture  of 


Fig.  45. — Floor  plan  and  arrangement  of  medical  inspector's  room  generally  fol- 
lowed in  New  York  City.  By  the  arrangements  indicated,  the  width  of  the  waiting 
room  may  be  used  in  eye  examinations  and  a  space  12  by  20  feet  is  sufficient  for 
both  waiting  room  and  examining  room.     (After  Berkowitz.) 

iodine,  sulphur  ointment,  white  precipitate  ointment,  vaseline, 
peroxide,  lysol,  aromatic  spirits  of  ammonia,  hand  scrub, 
tongue  depressors,  toothpicks,  argyrol,  cocaine,  bichloride  of 
mercury,  atropine,  alloy,  bluestone,  yellow  oxide  of  mercury, 
and  nitrate  of  silver. 

Administration. — Perhaps  the  best  way  to  describe  the  med- 
ical activities  in  school  hygiene  is  to  cite  the  example  of  a  city 
Avhich  has  developed  a  good  system  of  medical  inspection.    The 


282  HYGIENE :     DENTAL   AND    GENERAL 

city  of  Detroit,  Michigan,  which  has  a  population  of  900,000 
and  a  school  population  of  130,000,  has  perfected  a  division 
of  medical  school  inspection  under  the  Department  of  Health. 
The  present  activities  of  this  division  are  described  in  the 
monthly  bulletin  of  the  health  department  for  September, 
1919,  by  Henry  F.  Vaughan,  D.P.H.,  health  officer  for  the 
city. 

This  department  has  been  in  operation  for  ten  years  and 
records  show  that  communicable  diseases  among  school  chil- 
dren are  decreasing  from  year  to  year.  The  department  has 
established  a  routine  procedure  for  the  prompt  detection  of  in- 
fectious diseases,  for  exclusion  of  cases  from  school  under 
proper  quarantine  and  treatment  and  for  the  prompt  return 
of  the  pupils  to  school  after  the  quarantine  is  lifted.  School 
inspection  is  done  under  the  medical  director  who  has  in 
charge  50  medical  inspectors.  These  inspectors  visit  from 
three  to  five  schools  every  school  day  working  from  9.00  a.m. 
to  noon.  Standing  orders  have  been  issued  to  all  teachers  by 
the  Board  of  Education  through  the  agency  of  the  Department 
of  Health  to  send  promptly  to  the  examining  room  all  pupils 
coming  under  the  following  heads :  ( 1 )  children  who  were  ab- 
sent on  the  previous  day,  (2)  children  who  have  a  skin  erup- 
tion or  rash,  (3)  children  having  sore  throat  or  fever,  (4) 
children  having  persistent  cough  or  sore  throat.  The  teach- 
ers are  also  instructed  to  report  remedial  defects  among  chil- 
dren in  her  room  such  as  eye  and  ear  defects,  tonsils,  enlarged 
glands,  deformities,  etc.  This  places  a  burden  on  the  teacher 
which  normal  school  girls  are  not  well  equipped  to  bear  as 
they  are  trained  at  present.  Either  the  teacher  should  have 
more  training  in  the  detection  of  signs  of  infectious  disease 
and  bodily  defects  or  the  nurse  should  be  able  to  do  this  work 
in  the  school  room. 

In  Detroit  the  nurse  arrives  at  the  school  in  advance  of  the 
medical  inspector,  and  does  the  nonmedical  work,  being  able 
to  eliminate  some  of  the  pupils  sent  down  to  her  for  possible 


SCHOOL    HYGIENE  283 

exclusion  from  school.  All  eliilclreu  having  returned  to 
school  after  an  absence  are  questioned  and  on  the  average  two 
out  of  every  ten  questioned  are  excluded. 

For  instance,  Johnny  tells  the  nurse  that  he  was  absent  because  he 
had  a  sore  thioat.  In  answer  to  further  questions  Johnny  informs  the 
nurse  that  his  mother  and  two  other  members  of  the  family  are  suffer- 
ing from  sore  throat.  The  nurse  takes  a  culture  and  Johnny  is  sent 
home.  Later  in  the  day  she  A'isits  Johmiy  's  home  for  the  purpose  of 
making  a  more  extensive  survey.  If  her  suspicions  are  aroused  she 
telephones  to  the  Department  of  Health  and  a  diagnostician  is  sent 
to  the  house.  If  a  true  case  is  found  immediate  measures  are  taken 
to  quarantine  the  family. 

In  this  city  the  nurses  are  unable  to  do  much  work  in  the 
schoolroom  because  they  are  not  yet  supplied  in  sufficient 
numbers,  there  being  only  one  nurse  to  90(T0  pupils.  Dr. 
Vaughan  believes  that  the  ideal  proportion  is  one  nurse  for 
1500  to  3000  pupils. 

The  children  are  arranged  in  groups  for  the  attention  of 
the  medical  inspector,  so  that  he  finds  them  in  the  examining 
room  each  with  a  card  properly  made  out.  The  children  with 
sore  throats  are  in  one  group,  those  with  skin  rashes  in  an- 
other, etc.  The  medical  inspector  takes  up  the  work  of  the 
nurse  making  a  diagnosis  and  giving  to  the  principal  a  list  of 
the  children  to  be  sent  home.  It  is  Dr.  Yaughan's  practice 
to  recognize  the  presence  of  two  cases  of  a  communicable  dis- 
ease in  the  same  school  in  one  week  as  an  incipient  epidemic, 
in  which  ease  the  inspector  makes  an  examination  or  takes  a 
culture  of  every  child  in  the  school.  During  the  school  season 
a  physical  examination  is  made  of  every  school  child  so  that 
defects  which  are  overlooked  by  the  teacher  are  picked  up 
at  that  time.  All  schools,  public  and  parochial,  are  under 
the  Department  of  Health  Medical  Inspectors  and  an  impor- 
tant activity  of  the  general  i)hysical  examination  is  the  placing 
of  afflicted  children  in  special  schools  of  which  the  Board  of 
Education,  now  has  four  types  including  a  school  for  the  blind, 
one  for  crippled  children,  a  school  for  deaf  children  and  four 
open  air  schools. 


284 


HYGIENE:     DENTAL   AND    GENERAL 


Fig.  46. — The  effect  of  treatment  for  adenoids  upon  the  general  appearance  of 
three  children.  The  upper  picture  was  taken  before  treatment;  the  lower,  after 
treatment. 


Defective  Vision.- — Special  attention  must  be  given  to  the 
conservation  of  vision  and  the  correction  of  visual  defects,  for 
school  life  places  a  heavy  strain  upon  the  eyes.  The  accom- 
panj'ing  diagram  shows  the  physical  basis  of  far-sightedness 


SCHOOL   HYGIENE 


28f 


and  near-siglitedness  as  compared  with  normal  sight.  In  nor- 
mal sight  (emmetropia)  the  image  is  sharply  focused  on  the 
retina.  In  far  sight  (hypermetropia)  the  eye  ball  is  too  shal- 
low and  the  perfect  focus  of  the  image  would  take  place  be- 


Fig.  47. — Errors  in  refraction:  E  shows  the  formation  of  the  image  on  the  ret- 
ina in  the  normal  or  emmetropic  eye;  H  shows  the  condition  in  long-sight,  or  hy- 
permetropia, where  the  eyeball  is  too  short;  M  shows  the  condition  in  short-sight, 
or  myopia,  where  the  eyeball  is  too  long.      (Pearce-Macleod.) 


hind  the  retina.  There  is  therefore  a  blurred  image  and  in- 
distinct vision.  Hypermetropia  is  more  commonly  found  in 
young  children  and  many  of  these  cases  tend  to  correct  them- 
selves. However,  all  cases  where  eye  strain  is  involved  should 
receive  treatment. 

In  near  sight  (myopia)  the  eye  ball  is  too  deep  and  the 
image  is  focused  in  front  of  the  retina.  Myopia  is  a  more 
common  defect  among  older  children ;  it  is  a  more  serious  con- 
dition and  should  not  remain  untreated.  The  amount  of  my- 
opia increases  where  there  is  less  occasion  to  use  distant  vision. 


286  HYGIENE:     DENTAL   AND   GENERAL 

City  children  have  been  shown  to  have  more  near-sightedness 
than  conntry  children.  The  schools  themselves  may  be  re- 
sponsible for  some  degree  of  deterioration  of  vision.  This  is 
especially  true  if  the  student  holds  his  work  too  close  to  the 
eye.  There  are  many  factors  which  may  induce  near  or 
strained  vision  such  as  insufficient  light,  light  from  the  wrong 
direction,  a  strong  light  in  front  of  the  eyes,  faulty  position 
of  the  pupil  in  relation  to  the  blackboard,  faulty  illumination 
of  the  blackboard  producing  shiny  surfaces,  faulty  desks  and 
seats  leading  to  bad  postures  and  bending  of  the  head,  and  the 
condition  of  the  child's  general  health. 

Astigmatism  is  a  defect  of  a  different  type.  In  some  cases 
it  is  of  little  consequence  if  no  symptoms  are  produced  by  it. 
On  the  other  hand,  it  may  be  a  very  serious  defect  which  of 
itself  is  the  cause  of  ''eyestrain"  with  the  accompanying  head- 
aches and  poor  health.  This  is  a  condition  which  calls  for 
accurate  and  careful  correction.  There  are  different  kinds  of 
astigmatism,  according  as  the  eye  is,  in  the  vertical  and  hor- 
izontal meridians  respectively,  hypermetropic,  or  myopic.  In 
what  is  known  as  mixed  astigmatism,  there  is  hypermetropia 
in  one  meridian  and  myopia  in  the  other. 

The  Dental  Care  of  School  Children. — No  more  conclusive 
proof  of  the  importance  of  the  dental  care  of  school  children 
can  be  cited  than  to  describe  the  experience  of  cities  where 
school  hygiene  has  been  practiced  extensively.  The  work  at 
Bridgeport,  Conn.,  under  Dr.  Alfred  E.  Fones  has  been  more 
extensive  and  elaborate  than  that  in  any  other  American  city. 
It  is  not  out  of  place,  therefore,  to  consider  in  some  detail  the 
work  which  Bridgeport  has  carried  out.  The  total  number 
of  children  examined  and  treated  in  the  first  and  second 
grades  the  first  year  was  6,768.  On  the  first  examination  less 
than  ten  per  cent  Avere  brushing  their  teeth  daily.  About 
thirty  per  cent  claimed  that  they  brushed  their  teeth  occasion- 
ally, while  sixty  per  cent  were  frank  enough  to  state  that  they 
did  not  use  a  toothbrush.     Ten  per  cent  of  the  children  were 


SCHOOL   HYGIENE  287 

found  to  have  fistulas  on  the  gums,  showing  the  outlets  of  ab- 
scesses from  the  roots  of  decayed  teeth,  and  they  averaged  over 
seven  cavities  per  child.  "It  was  shocking,"  writes  Dr. 
Fones,  "to  find  the  mouths  of  these  children  five  to  seven  years 
of  age  in  this  deplorable  condition,  and  it  was  appalling  to 
contemplate  the  conditions  that  would  exist  in  these  mouths 
as  the  children  grew  up.  It  presented  very  interesting  ma- 
terial to  work  with. ' '  The  dentist  can  draw  his  own  picture 
of  the  evil  results  in  the  oral  cavity  and  in  the  system  gener- 
ally when  these  defects  remain  uncorrected. 

Dr.  Fones  made  the  following  statement  before  the  National 
Dental  Association  in  1917.  {Mouth  Hygiene  for  U.  S. 
Soldiers,  National  Dental  Association,  21st  Annual  Session, 
New  York,  October,  1917.) 

We  ]iave  tried  to  work  out  this  plan  in  Bridgeport,  and  after  three 
years  we  find  that  our  educational  and  preventive  dental  clinic  is  the  most 
important  part  of  our  school  and  health  systems.  Under  the  plan  of 
this  clinic  every  child  undergoes  an  examination  of  his  mouth  and  re- 
ceives a  prophylactic  treatment  of  his  teeth,  accepting  it  as  much  a 
part  of  the  school  curriculum  as  his  geography  lesson.  Every  child  is 
taught  a  method  of  brushing  his  teeth  and  is  educated  in  the  care  of 
his  mouth  just  as  he  is  taught  jDhysiology  or  calisthenics.  In  this  way 
the  municipality  accepts  one-half  the  responsibility  of  aiding  and  edu- 
cating the  children  in  the  prevention  of  dental  decay,  while  the  home 
care  of  the  mouth  and  proper  feeding  is  assumed  by  the  child  and  his 
parent. 

The  work  of  the  clinic  is  divided  into  four  distinct  parts.  First,  the 
actual  cleaning,  polishing,  and  examination  of  the  children 's  teeth  in 
schools.  Second,  the  toothbrush  drills  and  class  room  talks.  Third, 
stereopticon  lectures  for  the  education  of  children  in  the  higher  grades. 
Fourth,  educational  work  in  'the  home  carried  on  by  special  literature  to 
gain  the  cooperation  of  the  parents.  It  may  be  well  at  this  point  to 
make  clear  to  those  outside  the  dental  profession  what  a  prophylactic 
tieatment  really  is.  It  consists  mainly  in  the  thorough  cleaning,  by 
means  of  orange  wood  sticks  in  hand  polishers,  of  every  surface  of  every 
tooth.  This  means  the  removal  of  all  stains  and  accretions  on  the  teeth 
and  especially  of  the  sticky,  mucilaginous  films  known  as  bacterial 
placques,  which  are  the  initial  stage  of  all  dental  decay.  The  importance 
of  removing  these  placques  can  thus  be  readily  understood.  This  work 
of  prevention  of  dental  decay  is  essentially  a  woman's  work,  and  to  thi^ 


288  HYGIENE:     DENTAL   AND    GENERAL 

dental  hygienist  it  opens  up  paths  of  usefulness  and  activity  in  helping 
humanity  in  masses. 

In  1913-14  we  trained  the  first  class  of  dental  hygienists  in  Bridgeport, 
and  two  of  these  women  were  selected  as  dental  supervisors  when  our 
clinic  started  in  the  faU  of  1914.  We  had  received  $5,000  to  carry  on  a 
demonstrating  preventive  clinic  for  the  children  of  the  first  two  grades 
of  our  schools,  and  our  corps  consisted  of  eight  dental  hygienists  and  two 
supervisors.  In  but  one  year  our  city  officials  were  so  impressed  with 
the  results  of  our  work  that  the  appropriation  was  doubled,  the  corps 
enlarged,  and  a  woman  dentist  added,  and  now,  the  fourth  year  of  our 
clinic,  we  have  a  corps  of  twenty  dental  hygienists,  two  supervisors,  and 
two  women  dentists,  and  an  appropriation  of  $21,529.  The  money  is 
appropriated  through  the  board  of  health  and  the  clinic  is  conducted  by 
a  subcommittee  of  tMs  board. 

Time  will  not  permit  giving  a  detailed  report  of  our  clinic  from  its 
start  in  1914,  but  it  may  be  said  that  the  system  noAV  employed  is  very 
similar  to  that  used  originally. 

The  dental  supervisors  oversee  and  direct  the  work  of  the  dental 
hygienists,  give  classroom  talks,  toothbrush  drills,  stereopticon  lec- 
tures, and  attend  to  the  distribution  of  literature  to  children  and  sup- 
plies to  the  hygienists,  and  arrange  for  the  moving  and  location  of 
hygienists  in  each  school. 

The  work  of  the  dental  hygienists  consists  in  making  the  examination 
and  records  of  the  teeth,  giving  the  prophylactic  treatments  and  in- 
structions in  the  home  care  of  the  mouth. 

When  the  equipment  is  placed  the  hygienist  begins  work  for  the 
children  of  the  first  grade  and  takes  each  grade  in  succession  through 
the  fifth.  The  charts  are  made  of  each  child's  mouth,  one  for  the 
parent  and  one  which  is  a  permanent  record  for  the  files,  showing  the 
conditions  found  in  the  mouth  for  a  period  of  five  years. 

Aside  from  the  actual  cleaning  of  the  children's  teeth,  the  work 
of  the  supervisors  with  toothbrush  drills  is  considered  very  important, 
and  every  effort  is  made  to  present  this  phase  of  mouth  hygiene  to 
the  children  in  a  way  that  will  be  educational  and  interesting.  It  has 
been  quite  a  problem  to  secure  a  good  brush  that  can  be  sold  for  five 
cents,  and  up  to  the  present  time  nothing  better  has  offered  than  fac- 
tory seconds  of  a  good  make  of  brush. 

On  the  day  preceding  a  toothbrush  drill  a  notice  is  sent  to  the  parent 
requesting  that  the  child  be  allowed  to  bring  his  tooth  brush  to  school, 
and  that  it  be  securely  wrapped  in  clean  paper.  Announcement  is  made 
in  the  classrooms  that  any  child  may  purchase  a  new  toothbrush  for 
five  cents.  The  drill  proper  is  given  with  the  children  seated,  while 
the  assistants  pass  up  and  down  the  aisles  helping  the  children  to  hold 


SCHOOL    HYGIEXE  289 

the  brushes  coi-reetly  and  to  make  the  right  movements.  Theie  are 
four  positions  for  holding  tlie  brush  and  two  movements  in  each  drill. 
The  ehildren  brush  to  count  in  a  stereotyped  form,  it  V)eing  intended 
1<)  teach  merely  the  correct  form-  ■of  hrushinff  and  not  meant  for  the 
nctital  cleaning  of  the  tec'tli  "which  Avould  require  running  water  and 
dentifrice.  A  second  talk  is  given  up  to  the  care  of  the  brush  and  the 
necessity  of  hanging  it  in  a  clean  place.  The  ehildren  repeat  the  drill 
standing,  and  tlie  brushes  are  wrapped  in  clean  waxed  paper  to  be 
taken  homo. 

It  is  hardly  possible  to  estimate  the  educational  value  of  the  tooth- 
biusli  drill  in  the  classroom.  It  is  accepted  by  the  children  as  a  part 
of  the  curriculum,  and  therefore  something  to  be  learned  and  remem- 
bered. The  teachers  liave  aided  in  many  ways  to  assist  the  children  in 
forming  the  habit  of  daily  brushing. 

When  the  children  of  the  first  and  second  grades  receive  their  first 
treatment,  it  is  frequently  found  that  while  many  of  the  deciduous 
teeth  are  decayed,  the  few  permanent  teetli  erupted  at  that  age  are 
sound,  with  the  exception  of  the  six-year  molars.  The  very  first  small 
cavities  are  just  appearing  in  these  teeth,  and  we  believe  that  the  small 
children  entering  the  prophylactic  system  should  all  start  on  the  same 
basis,  that  is  with  sound  permanent  teeth.  We  have  two  women  den- 
tists who  work  with  the  hygienists  in  our  schools  and  confine  their 
efforts  to  the  filling  of  the  first  permanent  molar  teeth.  We  term  this 
preventive  dentistry  also,  as  the  effort  is  made  to  thus  prevent  the  de- 
velopment of  large  cavities  in  these,  the  most  important  teeth  of  the 
denture. 

Five  years  ago  Dr.  Fones  in  beginning  his  Avork  in  Bridge- 
port examined  the  mouths  of  the  children  of  the  fifth  grade. 
These  children  had  never  received  any  dental  attention.  In 
1919  he  again  examined  the  mouths  of  ehildren  of  the  fifth 
grade,  this  being  the  first  class  to  have  received  dental  care 
upon  entering  school.  The  beneficial  results  of  his  work  are 
shown  by  comparative  figures.  There  was  a  reduction  of 
caries  in  the  permanent  teeth  of  tlie  fifth  graders  amounting 
to  33.9  per  cent.  This  reduction  was  due  in  the  main  to  three 
activities,  (1)  cleaning  the  teeth,  (2)  filling  the  six-year  mo- 
lars, and  (3)  teaching  prophjdaxis  and  the  use  of  the  tooth- 
brush. 


290 


HYGIENE :     DENTAL   AND   GENERAL 


SCHOOL   HYGIENE  291 

The  following  story  of  the  experience  of  dental  clinics  in 
the  city  of  Detroit  is  told  in  the  September  (1919)  Bulletin 
of  that  city. 

Special  dental  clinics  are  maintained  for  school  children  at  fifteen 
different  locations  in  the  city.  The  clinics  are  so  situated  that  they 
will  be  conveniently  near  the  greatest  number  of  schools.  The  dental 
inspection  work  includes  all  tlie  schools  in  the  city,  public  and  parochial. 
-Tlie  children  are  sent  to  the  clinics  in  squads  at  appointed  hours  foi'' 
necessary  treatment. 

During  the  school  year  of  1918-19,  the  dental  clinics  accommodated 
73,245  children.  Of  this  number,  only  8,638  did  not  need  dental  atten- 
tion. The  necessity  for  this  inspection  work  is  emphasized  by  the  fig- 
ures in  the  report  showing  that  54,409  decayed  teeth  were  found  by  the 
inspectors,  the  number  of  permanent  molars  lost  being  9,046.  Nine  hun- 
dred and  ninety-two  children  were  found  suffering  from  abscesses, 
painful  and  health-destroying.     Fifty  children  had  palatal  defects. 

The  Department  of  Health  is  unable  to  reach  all  the  school  children, 
the  inspection  staff  being  limited  to  five  dentists,  and  not  all  of  them 
serving  during  the  full  school  year.  An  attempt  will  be  made  by  re- 
ducing the  reparative  work  and  increasing  the  prophylactic  work,  to 
take  care  of  new  schools  this  year.  It  has  been  the  jjlan  in  New  York 
City,  where  it  is  impossible  to  reach  all  the  school  children  needing 
dental  treatment,  to  select  children  from  the  age  of  school  entrance  up 
to  about  ten  or  twelve  years.  It  is  known  that  a  child's  mouth  during 
this  period  is  in  a  most  transitional  stage,  and  that  work  done  then  will 
have  a  great  effect  for  good  upon  the  future,  or  adult,  development  and 
condition  of  the  mouth. 

Enthusiastic  cooperation  on  the  part  of  teachers  and  principals  of 
schools  has  greatly  assisted  the  inspectors  in  their  work.  The  teachers, 
particularly  in  schools  where  dental  educational  propaganda  has  been 
conducted,  say  that  they  have  noticed  the  effect  upon  the  children,  es- 
pecially in  what  may  be  termed  the  improved  tone  of  the  pupils'  per- 
sonal hygiene.  Care  of  the  teeth  is  one  of  the  first  lessons  in  body 
cleanliness. 

The    teachers    and    pupils    assist    the    inspectors    by    collecting    an 
helping  to  fill  out  the  report  cards.     When  a  child  is  found  in  need  of 
dental  work,  the  Department  of  Health  sends  a  card  to  the  parents  or 
guardian,  reading  as  follows: 

' '  Your  child  needs  dental  attention.  This  is  the  time  to  have  the 
small  cavities  filled  to  prevent  future  loss  of  teeth.  If  you  have  a 
regular  family  dentist,  will  you  please  take  your  child  to  have  these 
cavities  fillcfl  while  most  of  them  are  yet  small.     If  you  have  no  regular 


292  HYGIENE:     DENTAL    AND   GENERAL 

dentist  and  positively  cannot  afford  to  pay  for  the  work  needed  for 
your  child,  you  may  have  such  work  done  without  charge  in  one  of  the 
free  dental  clinics  of  the  Department  of  Health.  If  you  wisli  this  done, 
please  sign  and  return  this  card  to  the  teacher  immediately. ' ' 

With  the  opening  of  the  present  school  season,  the  Department  of 
Health  dental  staff  comprises  fifteen  dentists  and  five  dental  liygienists. 
Under  a  new  state  law,  employment  of  dental  hygienists  for  dental  pro- 
phylactic work  is  permitted,  but  as  yet  the  department  has  been  unable 
to  interest  a  sufficient  number  of  qualified  dental  hygienists,  because 
they  are  largely  employed  in  eastern  cities. 

The  work  done  by  the  dentists  in  the  clinics  consists  of  filling,  ex- 
traction and  operative  treatment,  together  with  such  lectures  and  in- 
structions as  are  necessary.  In  addition,  69  cases  of  orthodontia, 
where  the  teeth  were  so  irregular  and  malformed  that  the  patients 
would  suffer  serious  physical  impairment  if  not  attended  to,  were  cor- 
rected during  the  year,  1,444  treatments  being  given  in  all. 

A  free  dental  clinic  is  maintained  on  the  third  floor  of  the  Depait- 
nient  of  Health  building,  233  St.  Antoine  street.  The  quarters  are 
rather  sm.all  for  the  volume  of  work  handled.  Five  chairs  are  in  opera- 
tion, in  addition  to  an  x-ray  room  and  orthodontia  room.  The  little 
patients  are  obliged  to  wait  in.  the  hall  for  their  turn  in  the  dental 
chair. 

However,  this  clinic  is  popular  during  the  twelve  months  in  the  year. 
In  addition  to  caring  for  school  children,  the  clinic  does  work  for-  others 
who  have  applied  for  employment  certificates,  but  who,  because  of  their 
teeth,  cannot  pass  the  required  pliysical  examination.  Adults  Avanting 
teeth  extracted  or  treatment  for  the  "toothache"  are  also  given  at- 
tention. 

WOEK   OF    SCHOOL   DENTAL    CLINICS 
1918-19 

New   cases    16,270 

Eevisits   22,765 

Total  visits  to  clinics  39,035 

Prophylactic  treatment   12,294 

Fillings 14,323 

Treatments     7,876 

Extractions — 

Deciduous   17,427 

Permanent    4,218 

Surgical  cases    23 

Curetment     162 

X-rays  taken   124 


SCHOOL    HYGIENE  293 

It  is  found  necessary  for  the  physician  or  dentist  in  charge 
of  medical  and  dental  school  supervision  to  show  the  results 
of  his  work  in  reports  issued  from  time  to  time  which  will 
secure  for  him  the  further  cooperation  and  financial  support 
of  the  city.  His  records  should  be  made  and  kept  with  this 
in  view.  We  have  already  cited  the  reduction  in  dental  caries 
at  Bridgeport  since  the  installation  of  the  dental  clinic.  The 
Health  Department  at  Bridgeport  is  also  able  to  show  the 
benefits  of  medical  and  dental  work  in  the  reduction  of  the 
percentage  of  retarded  pupils  as  shown  in  the  following  table : 

PERCENTAGE  OF  EETAEDED  PUPILS 


Grade  Sept.,    1912         Nov.,   1918 


Drop  ill 
Retardation 


1 16.5%  8.1%  51% 

II 37.  15.3  58 

III 53.  24.7  53 

IV 59.5  31.7  47 

V , 61.  33.1  45 

VI 54.  30.4  44 

VII 39.  19.3  50 

VIII 27.  12.0  54 


Average 4U%  20.1%  50% 

The  cost  of  reeducation  in  Bridgeport  in  1912  was  42  per 
cent  of  the  entire  budget,  whereas  in  1918  it  was  only  17  per 
cent.  A  careful  examination  of  conditions  showed  that  the 
only  changes  in  school  management  which  have  taken  place 
during  this  period  which  might  account  for  the  imin-ovement 
in  the  number  of  promotions  are,  (1)  an  effective  reorganiza- 
tion of  the  courses  of  study  which  took  place  in  1915  and  (2) 
the  establishment  of  dental  services  in  1912  with  better  medi- 
cal as  well  as  dental  supervision.  A  clear  case  is  therefore 
made  for  the  benefit  of  health  improvement  and  a  return  on 
the  investment  can  be  measured  by  the  saving  in  reeduca- 
tion costs. 


294  HYGIENE:     DENTAL   AND    GENERAL 

The  reduction  in  the  amount  of  certain  communicable  dis- 
eases also  can  often  be  attributed  to  school  medical  adminis- 
tration. In  presenting  data  of  this  sort  the  school  doctor  and 
particularly  the  school  dentist  must  be  very  careful  to  claim 
only  what  saving  can  actually  be  shown  to  be  due  to  his  own 
work.  For  example  the  city  just  referred  to  would  show  a 
marked  reduction  in  the  amount  of  communicable  diseases 
among  school  children  which  is  probably  due  quite  as  much 
to  the  establishment  of  an  efficient  system  of  general  health 
administration  with  the  employment  of  an  exceptionally  well 
trained  health  officer,  in  the  person  of  Dr.  Walter  H.  Brown, 
as  to  the  establishment  of  special  activities  in  school  hygiene. 
School  health  and  municipal  health  react  upon  each  other. 

2.  TEACHING  HYGIENE  IN  SCHOOLS 

There  are  some  diseases  like  typhoid  fever,  malaria  and  yel- 
low fever  which  can  be  nearly  eradicated  by  sanitation.  In- 
fluenza on  the  other  hand  is  an  example  of  a  group  of  diseases 
for  which  the  greatest  hope  of  control  lies  in  proper  personal 
hygiene.  During  the  epidemic  of  1918  thousands  of  people 
died  because  of  the  lack  of  knowledge  of  the  fundamentals 
of  home  nursing.  During  this  epidemic  the  visit  of  the  physi- 
cian and  nurse  was  occasional,  at  best.  Many  deaths  occurred 
because  the  wife  or  mother  caring  for  the  case  did  not  know- 
that  the  patient  with  pneumonia  must  not  get  up,  that  he 
needed  nourishment  regularly  even  though  he  did  not  want 
food  and  that  he  must  take  a  reasonable  amount  of  liquids. 
This  experience  has  taught  us  the  need  of  giving  our  children 
a  better  knowledge  of  hygiene  through  the  school  system. 

"We  have  spoken  of  instruction  in  mouth  hygiene  in  con- 
nection with  the  work  of  the  dental  hygienist.  Other  habits 
of  hygiene  are  inculcated  by  giving  the  pupil  a  list  of  spe- 
cific directions  for  his  daily  routine.  The  following  is  taken 
from  an  educational  bulletin  issued  by  the  Board  of  Health 
of  Bridgeport; 


SCHOOL   HYGIENE  295 

MY  DAILY  EOUTINE 

1.  Have  a  certain  time  for  rising  and  keep  to  it. 

2.  Throw  bed  clothes  over  foot  of  bed. 

3.  Wash  face   and  hands,   neck  and   ears  Avith  hot  water   and   soap. 

Einse  off  with  cold  water. 

4.  Brush  teeth  and  gums  with  clear  water. 

5.  Clean  finger  nails. 

6.  Brush  the  hair. 

7.  Inspect  clothes  as  to  cleanliness  and  see  that  shoes  are  brushed. 

8.  At  breakfast,  eat  slowly  and  chew  food  well. 

9.  Visit  the  toilet,  washing  afterward. 

10.  After  breakfast  brush  the  food  from  the  teeth,  using  tooth  powder 

or  paste. 

11.  Obey  rules  about  entering  school;  be  on  time. 

12.  Be  careful  to  sit  erect  and  to  stand  up  straight. 

13.  .Drink  water  at  recess. 

14.  Return  home  to  lunch  or  dinner  promptly  and  Avash  hands  before 

eating  and  brush  hair. 

15.  After  lunch  or   dinner  brush   the   food   from  the   teeth,   using  a 

tooth  powder  or  paste. 

16.  Play  in  the  fresh  air  after  school. 

17.  Before  eating  supper,  wash  the  hands  and  face  and  brush  the  hair. 

18.  Before  taking  off  the  shoes  to  go  to  bed,  brush  the  food  from 

supper  off  from  the  teeth  with  a  tooth  poAvder  or  paste.  Pass 
a  silk  floss  or  thread  betAveen  the  teeth  to  remove  the  food  there 
and  rinse  the  mouth  AA'ith  lime  water,  then  rinse  with  clear  warm 
water.  This  is  the  most  important  time  to  thoroughly  clean  the 
teeth. 

19.  See  that  clothes  are  neatly  placed  in  a  chair  after  undressing. 

20.  Visit  the  toilet,  washing  afterward. 

21.  Open  bedroom  Avindow  not  less  than  six  inches  from  top  and  bottom 

for  fresh  air.     If  AA'eather  is  not  too  cold,  open  Avider. 

22.  Be  sure  to  bathe  the  body  not  less  than  tAA'ice  a  Avcek. 

Such  work  succeeds  best  if  the  interest  of  the  children  is 
stimuhited  by  the  organization  of  some  child  health  societj'' 
Avhieh  has  promotions  for  progress  as  the  child  becomes  pro- 
ficient or  shows  a  good  record  in  personal  hygiene,  advancing 
the  boy  from  a  "squire"  to  a  ''page"  to  a  "knight"  etc.,  with 
corresponding  honors  for  the  girls.  Children  are  interested 
in  such  an  organization  when  properly  administered  and  they 
acquire  a  pride  in  physical  fitness  which  lasts  all  through  life, 


296  HYGIENE:     DENTAL   AND    GENERAL 

The  teaching  of  hj^giene  as  a  part  of  the  curriculum  in 
nearly  all  of  our  cities  can  be  improved  by  making  hygiene 
a  personal,  interesting  and  novel  subject.  Within  the  last 
few  years  we  have  made  a  distinct  gain  in  securing  text- 
books which  are  both  interesting  and  practical.  A  new 
organization  called  the  Society  for  Visual  Education  and 
having  headquarters  in  Chicago  is  able  to  supply  motion 
pictures  on  health  subjects  specially  prepared  for  school  chil- 
dren and  of  high  instruction  value.  Before  leaving  the  gram- 
mar school  the  child  should  be  given  not  only  the  principles 
of  personal  hygiene  but  a  knowledge  of  the  principles  of  in- 
fectious diseases  so  that  he  will  respect  the  authority  and  ac- 
tivity of  the  Health  Department  and  have  faith  in  their 
findings. 

In  the  high  school  personal  hygiene  should  be  continued  and 
perhaps  no  greater  step  in  improving  the  health  of  the  nation 
could  be  taken  than  to  require  of  every  girl  a  brief  course 
in  the  fundamentals  of  home  nursing.  Our  discussion  of 
school  hygiene  has  already  indicated  that  the  normal  schools, 
in  completing  the  training  of  teachers,  could  supply  them  with 
the  ability  to  do  much  for  their  pupils  if  they  trained  them  in 
the  princi]3les  of  schoolroom  sanitation,  the  effects  of  im- 
proper vetitilation,  lighting  and  heating  and  particularly  in 
the  facts  regarding  infectious  diseases  and  the  bodily  defects 
of  children. 

3.  SCHOOL  HYGIENE  AND  SANITATION 

The  maintenance  of  proper  school  hygiene  by  securing  suit- 
able lighting  and  ventilation,  proper  seating  and  proper 
habits  of  work  and  play  in  themselves  do  much  to  educate 
the  child  in  matters  of  personal  hygiene. 

The  dentist  is  not  ordinarily  concerned  or  burdened  with 
the  responsibilities  for  school  sanitation.  These  responsibil- 
ities fall  upon  the  health  and  school  departments.  We  are 
discussing  elsewhere  some  of  the  principles  of  water  supply, 
waste  disposal,  ventilation,  heating,  and  lighting  so  that  it 


SCHOOL    HYGIENE  297 

is  not  advisable  to  go  into  detail  on  this  subject,  for  in  any 
ease,  the  public  health  experts  should  be  consulted  and  should 
the  dentist  find  himself  responsible  for  regulating  these  fac- 
tors of  school  hygiene  a  more  extensive  work  should  be  sought. 

There  are  innumerable  details.  Safe  vi^ater  must  be  pro- 
vided and  distributed  through  individual  cups  or  by  drinking 
fountains  which  are  so  guarded  that  they  cannot  be  mouthed 
b}''  the  children  when  they  drink.  Enough  light  must  be  sup- 
plied from  the  pupil 's  left  or  from  very  high  at  the  right  and 
never  from  the  front  or  rear.  The  blackboard  must  receive 
sufficient  light  and  present  a  dull  surface.  No  seats  should 
be  so  far  from  the  light  as  to  make  it  difficult  for  the  pupil 
to  read.  The  entrance  and  cloak  room  should  be  sufficiently 
large  and  properly  ventilated  with  space  for  hanging  clothes 
and  a  place  for  wiping  the  feet.  The  entrance  should  not  be 
directly  on  the  street  and  there  should  be  one  entrance  for 
300  pupils.  Windows  should  be  regular  with  small  spaces  be- 
tween them  and  should  have  small  white  frames  which  open 
easily  at  the  top.  Dust  should  be  avoided,  in  so  far  as  pos- 
sible, by  wiping  boards  with  a  damp  cloth  and  by  preventing 
the  stirring  up  of  the  dust  immediately  before  school  or  at 
recess  since  it  takes  from  fifteen  minutes  to  one  hour  for  dust 
to  settle.  The  ventilation  system  should  supply  a  constant 
change  of  air  at  the  proper  temperature. 

The  length  and  width  of  schoolrooms  should  be  in  the  ap- 
proximate ratio  of  3  to  2.  In  room  construction,  corners 
should  be  avoided  for  ease  in  cleaning.  The  walls  should  be 
a  light  green  with  the  upper  three  feet  whitened  and  the  lower 
five  feet  may  well  be  of  tiling  or  some  such  durable  material. 
Ceilings  should  be  kept  white  and  the  floor  of  hard  wood  kept 
smooth.  Holes  in  the  floor  may  be  filled  with  a  mixture  of 
curd  and  slaked  lime  in  i)roporTion  of  five  to  one.  This  pro- 
duces a  hard  waterproof  cement. 

The  pupil's  desk  should  be  selected  with  care.  It  should 
not  have  sharp  corners,  it  sliould  be  easy  to  clean,  it  should 
not  interfere  with  the  teacher's  view  of  the  pupil,  it  should  be 


298  HYGIENE:     DENTAL   AND    GENERAL 

noiseless  and  so  shaped  that  the  sitting  posture  is  not  likely  to 
harm  the  spine,  thorax  or  the  eye.  There  should  be  measur- 
ing and  reseating  of  pupils  in  seats  of  proper  size  at  least 
two  times  a  year.  This  is  easier  if  one  third  of  the  seats  in 
the  room  are  adjustable  since  classes  vary  in  the  size  of  pupils. 
The  top  of  the  desk  should  be  on  a  plane  with  the  elbow. 
If  it  is  lower  than  this  the  spine  is  injured.  The  back  rest 
should  at  least  support  the  lower  third  of  the  spine.  Spit 
cups  or  cuspidors  should  be  provided  if  necessary. 

The  toilets  should  be  in  a  convenient  place  so  that  retention 
which  may  lead  to  maiming  or  weakening  the  bladder  or  pro- 
ducing sex  irregularities  may  be  avoided.  The  toilet  should 
be  well  ventilated  and  the  seat  should  be  sufficiently  low  and 
U-shaped.  Epidemic  vulvovaginitis  has  been  reported  in 
schools  as  having  spread  from  toilet  seats  so  high  that  it  was 
necessary  for  small  girls  to  drag  themselves  over  the  front. 

Age  and  Sex  Differences. — There  are  many  other  facts 
which  must  be  kept  in  mind  in  school  administration.  The 
brain  of  the  child  grows  rapidly  until  the  age  of  seven.  The 
school  life  should  not  be  begun  before  six  and  then  the  change 
should  not  be  abrupt.  European  examinations  (Monnard,  at 
Halle,  Germany)  show  that  there  is  less  increase  in  the  height 
and  weight  of  the  child  during  the  first  year  of  school  life 
than  in  any  period  up  to  14  years  of  age.  This  decrease  in 
the  rate  of  growth  was  not  noticeable,  however,  in  children 
who  did  not  enter  school  until  the  seventh  year.  Hertel,  of 
Copenhagen,  found  on  examination  of  thousands  of  chil- 
dren an  increase  in  the  amount  of  illness  on  school  entrance. 

Grirls  from  the  age  of  ten  to  fourteen  years  are  not  as  strong 
physically  as  boys.  The  Danish  Commission  examined  16,000 
boys  and  11,000  girls  and  found  29%  boys  and  41%  girls, 
respectively,  with  sick  records.  In  examining  300  children 
with  spinal  curvature  in  Berlin,  Eulenberg  found  that  13% 
were  boys  and  87%  were  girls.  Books  should  be  carried  with 
a  shoulder  strap  like  a  knapsack  and  not  in  one  arm.     They 


SCHOOL   HYGIENE  299 

should  not  exceed  a  fifth  of  the  weight  of  the  body.  Studies 
have  shown  more  illness  in  schools  of  two  sessions  than  in 
schools  of  one  session. 

Standards. — The  following-  set  of  Standard  Kequirements 
for  School  Children  issued  by  the  U.  S.  Department  of  Labor, 
Children's  Bureau  was  prepared  by  a  committee  of  public 
health  experts  and  adopted  at  the  Children's  Bureau  Confer- 
ence in  Boston  in  May  and  June,  1919  : 

1.  ProiDer  location,  constructiou,  hygiene  and  sanitation  of  school- 
houses;  adequate  room  space — no  overcrowding. 

2.  Adequate  playground  and  recreational  facilities;  pliysical  training, 
and  supervised  recreation. 

3.  Open-air  classes  and  rest  periods  for  pretubercular  and  certain 
tuberculous  children  needing  some  form  of  special  instruction  due  to 
physical  or  mental  defect. 

4.  Full-time  school  nurse  for  not  more  than  1,000  children  to  give  in- 
struction in  personal  hygiene  and  diet,  to  make  home  visits  to  advise  and 
instruct  mothers  in  principles  of  hygiene,  nutrition,  and  selection  of 
family  diet,  and  to  take  children  to  clinics  with  permission  of  parents. 

5.  Adequate  space  and  equipment  for  school  medical  work  and  avail- 
able laboratory  service. 

6.  Part-time  physician  with  one  full-time  nurse  for  not  more  than  2,000 
children,  or  full-time  physician  with  two  full-time  nurses  for  4,000  chil- 
dren for: 

(a)  Complete  standardized  basic  physical  examinations  once  a  year, 

with  determination  of  weight  and  height  at  beginning  and  end 
of  each  school  year;  monthly  weighing  wherever  possible. 

(b)  Continuous  health  record  for  each  child  to  be  kept  on  file  with 

other  records  of  the  pupil.  This  should  be  a  continuation  of 
the  preschool  health  record  which  should  accompany  the  child 
to  school. 

(c)  Special    examinations    to    be    made    of    children    referred    by 

teacher    or    nurse. 

(d)  Supervision  to  control  conmiunicable  disease. 

(e)  Eecommendation  of  treatment  for  all  remediable  defects,  dis- 

eases, deformities,  and  cases  of  malnutrition. 

(f)  Follow-up  work  by  nurse  to  see  that  physician's  recommenda- 

tions arc  carried  out. 


300  HYGIENE  :     DENTAL    AND    GENERAL 

7.  Available   clinics   for   dentistry,   nose,   throat,   eye,   ear,   skin,   and 
orthopedic  work;  and  for  free  vaccination  for  smallpox  and  typhoid. 

8.  Nutrition  classes  for  physically  subnormal  children,  and  the  main- 
tenance of  midmorning  lunch  or  hot  noonday  meal  when  necessary. 

9.  Examination  by  psychiatrist  of  all  atypical  or  retarded  children. 

10.  Education  of  school  child  in  health  essentials. 

11.  General  educational   work   in  health   and   hygiene,   including  edu- 
cation of  parent  and  teaclier,  to  secure  full  cooperation  in  health  program. 


CHAPTER  XV 

INDUSTRIAL  HYGIENE 

Dental  and  Medical  service  is  rapidly  increasing  in  indus- 
try. Already  more  than  100  firms  in  the  United  States  have 
fairly  complete  departments  of  industrial  hygiene  which  in- 
clude dental  clinics.  Dental  practise  in  an  industry,  there- 
fore, is  a  field  which  more  dentists  are  sure  to  enter.  For 
those  men  the  subject  of  industral  hygiene  holds  special  in- 
terest. But  for  the  dentist  who  is  sure  to  continue  in  private 
practice  industrial  hygiene  has  an  appeal  from  two  points  of 
view.  In  the  first  place,  he  is  interested  in  knowing  those 
industrial  poisons  which  have  mouth  lesions  which  he  should 
recognize  in  the  conduct  of  his  professional  activities,  and  in 
the  second  place  he  is  interested  in  knowing  w^hat  proportions 
industrial  hygiene  is  likely  to  assume  in  the  near  future  and 
the  attitude  of  society,  the  employers  and  the  employees 
toward  this  subject.  A  discussion  of  the  subject  from  this 
point  of  view  naturally  falls  under  three  heads:  (1)  the  im- 
portance and  social  aspects  of  the  problem;  (2)  the  health 
organization  of  industry;  and  (3)  the  industrial  diseases  to 
be  seen  in  dental  practice. 

GENERAL  ASPECTS  OF  INDUSTRIAL  HYGIENE 

The  health  of  the  worker  is  a  fundamental  national  problem. 
The  great  majority  of  our  vast  population  belong  to  the  group 
of  workers,  and  the  social  and  economic  aspects  of  the  ques- 
tion are  interrelated  with  health  conditions.  Upon  the  eon- 
tentedncss  of  the  industrial  classes  and  upon  their  physical 
well  being  rests  the  stability  of  our  social  system.  The  crafts- 
man of  the  Middle  Ages  with  an  interest  in  the  technique  of 
his  work  amounting  to  the  professional  pride  of  any  genera- 

301 


302  HYGIENE :    dentaIj  and  general 

tion,  no  longer  exists.  The  skill  of  tlie  hand  has  been  sup- 
planted by  the  precision  of  the  machine.  This  change  is 
fundamental,  for  the  laborer  no  longer  secures  much  of  his 
enjoyment  of  life  from  his  work  but  endeavors  rather  to  earn 
enough  to  be  able  to  purchase  his  amusement  out  of  working 
hours.  This  important  and  unfortunate  change  has  deprived 
the  worker,  in  most  cases,  of  a  pride  in  his  occupation  and 
centered  his  mind  so  completely  upon  the  financial  return  that 
he  is  not  as  interested  as  he  should  be  in  the  conditions  under 
which  lie  works.  To  be  sure  labor  of  late  has,  in  many  cases, 
demanded  better  working  conditions;  but  more  instances  can 
be  found  where  laborers  used  unhygienic  conditions  as  a  basis 
of  the  demand  for  more  wages  and  not  as  a  basis  for  demand- 
ing better  health  conditions. 

In  the  Middle  Ages  the  craftsman  had  joy  and  pride  in  his 
work  akin  to  that  of  the  surgeon  or  the  dentist  who  is  con- 
tinually improving  his  skill  and  technique.  The  old  Guilds 
maintained  a  form  of  accident  and  sickness  insurance;  they 
appointed  inspectors  to  see  that  the  work  was  properly  done 
and  honest  labor  was  their  watchword.  The  craftsman  knew 
the  entire  process  of  making  the  article  on  which  he  was  work- 
ing and  he  knew  that  his  return  would  be  proportional  to  his 
endeavor.  The  broad  interests  and  the  social  organization  of 
the  Trade  Guilds  reached  a  height  to  which  the  existing  labor 
unions  have  not  attained. 

We  are  probably  moving  toward  a  condition  of  cooperation 
in  industry,  but  under  present  conditions  it  is  most  difficult 
to  give  the  workman  the  old  time  interest  in  what  he  is  doing. 
He  knows  only  a  bit  of  the  process  of  manufacture,  the  indus- 
try is  so  large  that  he  is  widely  removed  from  the  man  at  its 
head;  there  is  in  many  cases  worse  than  a  lack  of  sympathy 
between  employer  and  employee,  and  the  high  labor  turnover 
testifies  to  the  lack  of  interest  of  the  workman  in  his  partic- 
ular factory.  The  return  of  the  worker's  interest  in  his  work 
and  in  the  conditions  of  labor  would  greatly  aid  the  prog- 


INDUSTRIAL    HYGIENE  303 

ress  of  the  health  movement.  But  the  latter  movement  need 
not  be  delayed  for  the  former,  for  its  solntion  will  help  to  solve 
the  economic  problem. 

This  unfortunate  industrial  condition  of  class  selfishness  in 
which  labor  and  capital  with  mutual  dislike  and  distrust  both 
profiteer  to  such  an  extent  that  unskilled  or  semi-skilled  labor 
receives  more  money  than  the  average  man  in  the  professions, 
while  capital  merely  adds  the  cost  of  increased  wages  to  the 
sales  prices  and  thereby  increases  both  the  value  of  its  prop- 
erty and  the  rate  of  its  return,  is  unfortunate  from  the  eco- 
nomic point  of  view.  But  industrial  distrust  in  place  of  in- 
dustrial cooperation  is  even  more  objectionable  from  the  view- 
point of  health. 

It  has  recently  happened,  for  example,  that  the  labor  unions 
of  a  great  industry  objected  to  the  continuation  of  physical 
examinations.  The  reasons  given  were  that  physical  examina- 
tions give  an  industry  the  opportunity  to  spread  propaganda 
favorable  to  capital  among  its  workers ;  that  there  is  an  oppor- 
tunity for  the  industry  to  discharge  "labor"  men  by  declar- 
ing them  physically  unfit ;  that  the  bodies  of  the  men  are  their 
own  and  that  capital  has  no  right  to  have  an  inspection ;  that 
the  physician  who  is  examining  the  men  will  testify  against 
them  in  court  if  they  have  a  case  against  the  company  for  in- 
dustrial accident;  that  industries  try  to  secure  the  goodwill 
of  the  general  public  by  expanding  the  health  work  for  em- 
ployees. 

Physical  examination  of  workers  as  carried  on  by  most 
industries,  coupled  with  the  attempt  to  relieve  those  body  de- 
fects which  are  found,  is  not  a  selfish  move  on  the  part  of  the 
industry'  and  such  objections  as  are  raised  above — and  which 
do  not  need  an  answer  in  a  discussion  for  professional  men — 
would  almost  make  it  appear  that  the  desire  to  broaden  the 
gulf  between  labor  and  capital  is  dominant  in  the  mind .  of 
the  labor  leader  w^ho  makes  these  objections.  His  interest  in 
the  welfare  of  the  worker  and  willingness  to  improve  indus- 
trial relations  does  not  appear.     It  does  happen  that  a  healthy 


304  HYGIENE:     DENTAL    AND    GENERAL 

worker,  free  from  bodily  defects  and  therefore  more  efficient 
and  contented,  is  more  profitable  to  the  industry  than  the 
same  man  encumbered  by  the  body  defects  with  which  he  fre- 
quently seeks  employment,  but  the  workman  wlio  objects  to 
being  made  well  and  happy  through  the  efforts  of  his  own 
doctor  or  those  of  the  industrial  physician,  surgeon  or  den- 
tist, folloAving  the  examination  Avhich  has  revealed  these  de- 
fects, comes  pretty  near  cutting  off  his  nose  to  spite  his  face. 

General  Problems. — There  are  many  considerations  in  the 
regulation  of  industry  which  apply  to  industries  generally 
and  which  are  regulated  both  from  without  by  the  state  and 
from  within  hy  the  industrial  management  and  the  demands 
of  organized  labor.  I  refer  to  such  problems  as  the  hours  of 
work,  fatigue,  child  labor  and  women  in  industry.  These  ques- 
tions with  their  interrelationships  have  such  a  universal  ap- 
plication that  it  is  the  duty  of  the  state,  first,  to  study  hy 
observation  and  research  the  conditions  of  employment; 
second,  by  careful  legislation  to  regulate  conditions  in  a  sane 
and  practical  manner  and,  third,  to  enforce  the  law  by  an 
efficient  organization  for  factory  inspection. 

Hours  of  Work. — The  number  of  hours  which  an  individual 
may  work  depends  largely  upon  the  nature  of  this  work.  If 
labor  were  paid  on  the  basis  of  production  and  interested  in 
maximum  production,  it  would  be  possible  to  arrange  for  each 
occupation  the  hours  of  labor  in  accordance  with  greatest 
efficiency  without  injuring  the  health  of  the  worker.  So  far 
as  the  state  is  concerned,  however,  it  must  deal  with  industries 
in  large  groups  and  set  standards  of  labor  in  terms  of  hours 
per  week  beyond  which  either  health  or  production  or  both 
are  likely  to  suffer. 

The  experiences  of  the  great  allied  countries  during  the  war 
have  taught  us  much  in  this  regard  and  the  investigations  be- 
gun under  war  conditions  are  likely  to  be  continued,  greatly 
to  the  profit  of  industry.     These  reports*  show  a  reduction  in 

*Report  of  the  Health  of  Munition  Workers,  Committee  of  the  Ministry  of 
Munitions,  published  by  His  Majesty's   vStationery  Office,   London,    1918. 


INDUSTRIAL    HYGIENE  305 

hourly  output  during  the  later  hours  of  the  8,  10,  and  12  hour 
working  day,  the  reduction  being  greatest  in  the  last  instance. 
The  relative  benefits  of  a  ten  minute  rest  period  in  the  eight 
or  ten  hour  day  and  the  great  advantages  of  Sunday  rest  are 
described.  Perhaps  no  more  striking  fact  was  brought  out 
than  the  discovery  that  the  weekly  production  on  the  six  day 
basis  was  equal  to  or  greater  than  the  weekly  production  on  a 
seven  day  basis. 

Fatigue. — Actual  and  careful  studies  within  industries 
made  by  expert  physiologists  are  rapidly  producing  a  new  sci- 
ence of  industrial  hygiene  and  physiology.  The  U.  S.  Public 
Health  Service  is  making  important  investigations  from  which 
we  may  hope  to  learn  much  concerning  the  effect  of  fatigue 
in  increasing  the  number  of  accidents,  in  decreasing  produc- 
tion, and  in  injuring  health.  The  great  need  in  this  field  at 
present  is  further  scientific  investigation  of  fatigue  in  the 
various  kinds  and  conditions  of  labor.  These  studies  will 
show  us  how  fatigue  may  be  reduced  by  modifying  processes, 
and  by  selecting  the  right  type  of  man  for  each  type  of  work. 
They  will  point  out  the  unnecessary  causes  of  fatigue  and 
show  what  innovations  may  be  made  to  avoid  them. 

Child  Labor. — Many  states  already  have  good  laws  prohibit- 
ing the  employment  of  child  labor,  but  even  the  best  of  these 
states  have  inadequate  machinery  for  inspection  and  enforce- 
ment. It  is  to  be  hoped  that  the  new  and  second  national 
child  labor  law  may  be  found  to  be  constitutional  and  go  far 
toward  remedying  these  conditions.  The  unrestricted  em- 
ployment of  children  in  industry  interferes  with  their  physical 
and  mental  development,  and  moreover,  children  have  been 
found  to  be  subject  to  industrial  accident  and  industrial  dis- 
eases to  a  greater  degree  than  adults. 

Women  in  Industry. — Special  legislation  is  frequently  nec- 
essary to  safeguard  the  health  of  women  because  they  lack 
strength  for  undertaking  many  occupations,  and  in  addition 
there  is  a  period  each  month  during  menstruation  and  a  longer 


306  HYGIENE:     DENTAL   AND    GENERAL 

period  at  the  termination  of  labor  when  heavy  employment 
should  not  be  allowed.  Most  states  require  that  a  woman 
shall  cease  work  from  two  to  four  weeks  before  labor  and  that 
she  shall  not  recommence  work  until  four  weeks  after  the 
birth  of  the  child.  Although  infant  mortality  increases  di- 
rectly with  the  proportion  of  women  working  outside  the  home, 
it  is  perhaps  unfortunate  that  states  cannot  legislate  regard- 
ing woman 's  work  in  the  home  which,  in  many  cases,  is  heavy, 
prolonged,  worrisome,  and  fatiguing  beyond  that  of  factory 
employment  but  which  receives  very  little  consideration  and 
is  difficult  to  remedy. 

Factory  Inspection. — Factory  inspection  involves  the  en- 
forcement of  laws  regulating  ventilation,  dusts,  gases,  odors, 
temperature,  moisture,  light,  cleanliness,  overcrowding,  water 
supply,  washing  facilities,  water  closets,  lockers,  fire  preven- 
tion, the  safeguarding  of  machinery,  first  aid  facilities,  hours 
of  labor,  employment  of  women  and  children,  ages  of  employ- 
ment, etc.  In  many  states  the  enforcement  of  these  laws 
is  under  the  State  Department  of  Health  and  enforcement  is 
a  reasonable  duty  of  the  Division  of  Industrial  Hygiene.  In 
other  states,  however,  it  is  under  a  separate  Department  of 
Labor  and  Industries  but  when  so  located  it  demands  much 
attention  from  the  medical  viewpoint,  especially  in  these  times 
when  so  much  is  being  learned  regarding  poisons  and  other 
industrial  hazards.  No  state  can  be  excused  for  not  investi- 
gating and  trying  to  lessen  the  health  and  accident  hazards 
of  the  industries  within  its  borders. 

Industrial  Accident  Insurance. — The  history  of  Employers' 
Liability  Acts  which  originated  in  Europe  and  which  were 
later  supplanted  both  in  Europe  and  America  by  industrial 
insurance  describes  a  step  forward  in  industrial  relations. 
Under  Employers'  Liability  the  workman  recovered  damages 
for  injury  by  accident  by  bringing  suit  against  the  employer 
and  it  was  necessary  for  him  to  prove  that  the  accident  was 
due  to  the  fault  or  negligence  of  the  employer  rather  than  to 
his  own  fault  or  that  of  a  fellow  worker.     Naturally  ill  will 


INDUSTRIAL.    IIYGIEXE  307 

arose  between  the  contending-  parties ;  the  amount  of  damages 
granted  often  depended  upon  the  case  and  the  court  rather 
than  upon  the  extent  of  the  injury;  and  there  was  usually 
a  long  delay  before  the  stricken  family  of  the  injured  worker 
received  any  benetit. 

Society  has  gradually  come  to  assume  that  the  industry  is 
responsible  for  all  accidents  occurring  in  its  processes  and  that 
the  workman  should  be  paid  promptly  and  in  proportion  to 
the  injury  or  incapacitation  incurred  in  the  execution  of  his 
duties  as  an  employee.  Accordingly  most  of  our  states  have 
now  enacted  industrial  insurance  acts  under  which  the  em- 
ployer insures  his  liability  with  the  state  or  with  an  independ- 
ent insurance  company.  Under  such  a  law  the  employee  re- 
ceives benefits  from  any  accident  incurred  in  the  industry  and 
from  diseases  contracted  because  of  occupation.  It  is  not  nec- 
essary for  the  workman  to  prove  that  the  accident  was  the 
fault  of  the  employer  since  no  difference  is  made  between 
payment  in  such  accidents  and  in  those  due  to  the  fault  of  the 
worker,  unless  malicious  or  intentional.  Under  this  system 
the  workman  receives  compensation  after  a  Avaiting  period  of 
about  ten  days;  there  is  no  delay  or  expenditure  for  court 
procedure,  and  the  friction  between  employer  and  workman 
is  banished. 

HEALTH  ADMINISTRATION  IN  INDUSTRY 

Health  activities  in  industry  are  usually  carried  on  under 
a  service  department  and  under  the  administration  of  a  Serv- 
ice Manager  who  reports  directly  to  the  General  Manager. 
The  chart  on  pp.  308  and  309  used  with  permission  of  the 
Hood  Rubber  Company  gives  the  organization  and  activities 
of  one  of  the  most  complete  and  successful  service  depart- 
ments in  the  country. 

In  industries  where  the  service  department  has  been  given  a 
fair  trial  under  tactful  and  efficient  leadership,  it  has  clearly 
demonstrated   its   usefulness   and   both    employers    and    em- 


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310  HYGIENE :     DENTAL   AND    GENERAL 

ployees  have  come  to  regard  it  as  a  normal  and  natural  serv- 
ice which  the  manufacturer  should  render  to  the  workman 
under  the  conditions  of  his  employment.  More  than  that  it 
gives  opportunity  for  the  employee  to  better  his  own  con- 
ditions and  those  of  his  fellow  workers,  .thus  making  a  job  into 
a  career  and  a  mechanical  operation  into  a  human  relation- 
ship. It  is  a- new  and  i^roper  service  from  the  manufacturer 
which  is  bound  to  develop  as  has  accident  insurance  and  which 
will  soon  cease  to  be  resented  as  "charity"  by  the  workman, 
provided  of  course  that  it  is  properly  administered. 

The  activities  of  the  service  department  are  seen  to  be 
numerous  and  varied.  The  service  manager  muist  first  of  all 
be  a  good  administrator ;  he  must  know  the  industry ;  he  must 
understand  men  and  he  should  be  familiar  with  the  facts  con- 
cerning health  and  sanitation  and  the  principles  of  health 
administration.  He  may  be  a  sanitarian  or  a  physician  by 
training  but  in  any  case  he  is,  in  a  large  organization,  an 
administrator  and  can  secure  expert  services  and  delegate 
either  the  medical  or  engineering  responsibility. 

It  does  not  lie  within  the  scope  of  this  volume  to  describe 
the  multiple  activities  of  a  service  department.  The  number 
undertaken  and  the  details  of  administration  vary  widely. 
The  reader  is  most  interested  in  the  strictly  medical  and 
dental  phases  and  the  discussion  will  be  limited  accordingly, 
allowing  only  for  such  comment  upon  accident  prevention  and 
sanitation  as  will  show  the  close  relationships  which  they  bear 
to  health  improvement. 

Accident  Prevention. — Scientific  accident  prevention  has 
been  adopted  by  nearly  all  of  the  great  industries  where 
hazards  are  numerous  and  it  has  succeeded  because  it  is  prac- 
tical. It  has  been  demonstrated  that  by  j^roperly  safeguard- 
ing machinery  and  dangerous  processes  and  by  organizing  the 
men  for  safety,  the  number  of  accidents  can  be  markedly  re- 
duced. Accident  rates  have  been  reduced  80  per  cent  in 
some  industries  and  it  is  estimated  that  25  per  cent  of  this 
reduction  Avas  due  to  mechanical  safeguards  and  75  per  cent 


INDUSTRIAL    HYGIENE  311 

to  thoughtful  precautions  taken  by  the  men  themselves  as  a 
result  of  "Safety  First"  teachings.  This  reduces  the  suffer- 
ing of  the  men,  makes  the  work  more  desirable  and  it  reduces 
the  expenses  of  insurance  and  medical  attendance. 

Safety  engineers  have  often  been  men  without  an  engineer- 
ing training  but  men  of  good  mixing  ability  who  understood 
the  industry  and  who  were  able  to  organize  the  men  into 
safety  committees  and  follow  up  accidents  to  see  that  the 
proper  remedies  were  applied  for  dangerous  conditions.  It 
has  happened  frequently  that  safety  engineers  have  also  been 
interested  in  the  sanitation  of  the  plant  and  sometimes  to  an 
even  broader  extent  in  the  health  of  the  men.  It  is  often 
desirable  that  a  man  should  be  secured  for  this  work  whose 
training  enables  him  to  combine  sanitation  and  safety. 
Trained  men  will  soon  be  demanded  for  both  lines  of  work. 

Industrial  Sanitation. — The  duties  of  the  sanitary  en- 
gineer in  the  industry  are,  as  in  general  practise,  the  pro- 
vision of  water  supply  and  waste  disposal  to  which  are  likely 
to  be  added  problems  of  lighting,  heating,  and  ventilation. 
Principles  involved  in  these  activities  are  discussed  elsewhere 
and  the  particular  problems  of  industrial  sanitation  are  not 
of  interest  to  the  dental  practitioner.  The  supervision  of  eat- 
ing facilities  at  the  factory  will  serve  as  an  illustration  of  the 
direct  I'elationship  between  sanitation,  other  health  activities, 
and  the  health  and  efficiency  of  the  employee. 

Food. — The  supervision  of  such  restaurants  as  may  be  main- 
tained in  or  near  industries  may  logically  be  mentioned  as  a 
part  of  the  sanitation  of  the  industry  but  the  food  problem 
is  more  than  this.  Of  course  the  sanitation  of  the  restaurant, 
the  physical  examination  of  food  liandlers,  clean,  pasteurized 
milk,  adequate  dish  washing  facilities  for  complete  steriliza- 
tion and  sanitary  wash  rooms  and  toilets  for  food  handlers 
must  be  provided.     But  the  food  problem  does  not  end  here. 

In  the  steel-ship  industry  the  author  found  that  among 
60,000  men  in  about  40  shipyards  from  66  per  cent  to  90  per 
cent  brought  their  lunclies.     These  lunches  were  eaten  cold 


312  HYGIENE:     DENTAL    AND    GENERAL 

and  in  most  cases  were  not  balanced  from  the  dietetic  stand- 
point. Moreover  many  men  who  bought  lunches  at  the  cafe- 
terias paid  fifty  cents  for  their  lunch,  selecting  nothing  but 
desserts  and  many  of  these  were  of  the  pie  crust  and  whip 
cream  variety  with  relatively  little  nourishment.  In  this  in- 
dustry it  was  possible  to  secure  improvements  by  placing  cus- 
tards, bread  puddings,  blanc  mange,  and  other  nourishing 
foods  on  the  list  of  desserts  and  by  placing  booths  at  various 
points  about  the  shipyard  from  which  hot  coffee  and  hot  stew 
were  served  in  sanitary  individual  containers  to  supplement 
the  cold  lunches  brought  from  home. 

By  enlisting  the  help  of  the  community  health  organizations 
in  the  food  program,  it  was  possible  to  secure  practical  demon- 
strations of  how  to  prepare  suitable  lunches  with  a  saving  in 
expense,  and  further  suggestions  were  supplied  through 
columns  of  the  monthly  paper  issued  by  the  industrj''.  The 
results  of  the  campaign  were  most  gratifying  and  the  incident 
illustrates  how  sanitary  and  medical  supervision,  health  edu- 
cation and  the  cooperation  of  the  shop  committees,  the  man- 
agement and  the  health  interests  of  the  community  must  often 
combine  for  a  health  improvement. 

Medical  Activities. — The  medical  organization  of  an  indus- 
try is  to  maintain  the  health  of  the  working  force  and  its  ob- 
ject is  threefold ;  first,  to  care  for  the  man  who  becomes  sick 
or  injured  while  at  work;  second,  to  detect  and  correct  defects 
which  are  remedial;  and  third,  to  detect  diseased  conditions 
in  new  employees  which  would  endanger  their  own  lives  or 
those  of  their  fellow  workmen  thus  making  it  possible  to  tem- 
porarily exclude  or  restrict  the  employment  of  this  type  of 
worker.  This  very  important  function  is  mentioned  last  be- 
cause many  medical  departments  exist  where  there  is  not  as 
yet  either  a  physical  examination  upon  employment  or  a 
periodical  examination  of  the  workers.  The  United  States, 
our  greatest  employer,  has  recently  examined  what  was  at  the 
time  its  most  important  group  of  workers  (soldiers  and  sail- 
ors)  and  has  attempted  to  remedy  some  of  the  physical  de- 


INDUSTRIAL    HYGIENE  318 

fects  found.  These  men  were  picked  from  the  age  groups 
in  which  they  are  supposedly  most  vigorous  and  even  then 
from  one  third  to  one  half  of  them  were  unfit  for  full  military 
service.     The  following  are  the  physical  defects  found: 


TABLE  SHOWING  CAUSES  EOR  DRAFT  REJECTION 

PER  CENT 
CAUSES  ALL 

REJECTIONS 

Total  rejections,  for  all  causes 100.00 


Alcohol  aud  drugs 43 

Bones  and  joints 12.35 

Development  defects  (height,  weight,  chest  measurements,  muscles)  8.37 

Digestive  sj'stera 53 

Ears     4.38 

Eyes 10.65 

i'latfoot  (pathological)    3.87 

Genitourinary  (venereal)   1.33 

Genitourinary    (non-venereal) 1.35 

Heart  and  blood  vessels 13.07 

Hernia 6.04 

Mental  deficiency    5.24 

Nervous  and  mental  disorders   5.07 

Respiratory   (tuberculosis)    8.67 

Respiratory    (nontuberculosis)     1.67 

Skin  .  .  . .  " 2.68 

Teeth 3.16 

Thyroid 1-76 

Tuberculosis  (of  parts  other  than  respiratory)    88 

All  other  defects 3.06 

Cause  not  given    5-44 

The  industry  is  in  much  the  same  position  as  the  govern- 
ment. It  not  only  owes  to  the  individual  compensation  for 
accident  or  illness  acquired  as  a  result  of  his  occupation,  but 
it  also  owes  to  the  individual  a  knowledge  of  his  physical  con- 
dition, and  the  applicant  should  be  so  placed  in  the  industry 
as  not  to  aggravate  his  physical  condition.  It  owes  to  the 
workers  alread}^  in  the  plant  protection  against  the  entrance 
of  infectious  disease. 


314  HYGIENE:     DENTAL   AND    GENERAL 

A  great  service  can  be  rendered  in  improving  the  health  of 
the  industrial  class  by  offering  free  medical  examination.  The 
vi^orkman  is  warned  of  a  defect  while  it  is  still  remediable  and 
the  young  man  is  impressed  with  the  importance  of  health 
when  he  looks  forAvard  to  a  physical  examination  as  part  of 
the  process  of  "getting  a  job!"  It  may  seem  to  the  private 
practitioner  of  medicine  and  dentistry  that  the  individual 
should  merely  be  apprised  of  his  physical  condition  and  that 
he  should  seek  medical  treatment  outside  the  industry.  This, 
of  course,  is  what  happens  in  a  great  number  of  cases.  The 
worker  always  possesses  the  right  to  choose  his  physician  and 
mode  of  treatment  and  frequently  prefers  to  go  to  his  family 
physician  or  dentist.  On  the  other  hand,  however,  there  is 
no  reason  why  the  industry  should  not,  if  it  chooses,  offer  to 
the  workman  medical  and  dental  care  free  or  at  slight  cost. 
The  industry  can  frequently  afford  to  do  so  as  there  is  less 
lost  time  for  the  industry  and  for  the  employee  when  treat- 
ment is  given  at  the  factory. 

The  employee  is  insured  against  industrial  accidents  and 
industrial  diseases  and  there  is  no  obligation  upon  the  indus- 
try or  the  insuring  company  to  treat  anything  more  than  acci- 
dent cases.  Even  M^here  there  is  not  a  well  organized  service 
department,  however,  it  is  usually  the  policy  to  treat  em- 
ployees for  minor  ills  such  as  headache,  toothache,  stomach 
cramps  and  the  like,  for  which  it  is  known  they  would  not  be 
likely  to  consult  a  physician. 

An  example  of  the  value  of  a  medical  department  may  be 
seen  in  the  experience  of  an  industrial  establishment  {Modern 
Hospital,  July,  1919)  which  offered  optional  physical  exami- 
nations under  the  supervision  of  the  Life  Extension  Institute 
beginning  in  May,  1915.  Seventy  per  cent  of  the  workers  were 
examined  and  examinations  were  repeated  in  the  three  suc- 
ceeding years.  Later  it  was  made  compulsory  for  new  employ- 
ees. Out  of  599  examined,  ovAj  5  were  found  to  be  normal ; 
594  required  advice  regarding  their  living  habits  or  physical 
condition ;  377  were  directed  to  a  physician,  and  of  these  317 


INDUSTRIAL    HYGIENE  315 

were  not  aware  of  any  impairment  whatsoever.  The  em- 
ployees who,  by  later  investigations,  were  found  to  be  carry- 
ing out  instructions  numbered  361 ;  those  carrying  them  out 
partially-,  66 ;  those  making  plans  to  do  so,  12 ;  those  who  had 
done  nothing,  160.  Hence  439  of  the  employees  have,  or  will 
have  been  benefited.  Poor  eye-sight,  teeth,  heart  disease,  and 
incipient  tuberculosis  are  particularly  mentioned. 

If  the  industrial  physician  or  dentist  is  efficient  and  under- 
stands his  position  and  the  relationships  of  his  department  to 
the  workmen  in  the  plant,  the  medical  department  is  an  aid 
to  the  industry  in  many  ways.  The  industrial  dentist  and 
physician  may  be  nearly  or  completely  engrossed  in  admin- 
istering professional  services  which  only  slightly  differ  from 
those  of  private  practise,  although  there  are  certain  indus- 
trial diseases  with  which  both  must  be  familiar.  However, 
to  be  successful  each  must  carry,  in  addition  to  his  professional 
knowledge,  the  ability  to  command  the  friendship  and  respect 
of  the  men  who  come  to  him  for  treatment  and  to  impress 
upon  his  patients  the  value  and  propriety  of  the  sort  of  work 
he  is  doing.  The  dentist  must  not  allow  the  false  idea  to  exist 
that  the  dental  clinic  is  a  "patronizing"  activity.  It  is  a 
function  of  the  industry  to  which  the  workman  is  entitled  and 
it  can  only  be  successful  by  an  appreciation  of  its  usefulness 
and  by  the  cooperation  of  the  workmen  in  the  factory.  The 
policy  of  the  hospital  and  clinic  must  be  clearly  established 
and  thoroughly  understood  by  the  medical  and  dental  person- 
nel and  by  the  management,  and  this  policy  must  be  strictly 
adhered  to.  The  same  dignity  should  be  maintained  as  in 
private  practise  and  under  no  conditions  should  the  clinic  be- 
come a  place  for  loitering  or  for  unreasonably  frequent  visits 
by  employees. 

Industrial  Dentistry. — It  is  not  difficult  to  prove  the  need 
of  dental  care  for  the  industrial  worker.  In  examining  large 
groups  of  industrial  workers,  it  has  been  found  that  90  per 
cent  or  more  of  such  people  have  dental  defects.  Thousands 
of  men  were  excluded  from  general  military  service  because 


316  HYGIENE:     DENTAL   AND   GENERAL 

of  dental  defects,  and  it  is  no  wonder  that  now — when  an  in- 
creasing- number  of  bodily  defects  are  found  to  be  due  pri- 
marily or  in  part  to  local  infections  about  the  teeth — the  im- 
portance of  expert  dental  services  begins  to  receive  general 
recognition. 

The  dental  clinics  which  have  been  established  in  various 
industries  are  not  uniform  in  their  methods  of  administration. 
The  dentist  may  be  full  time  or  part  time.  Some  industrial 
clinics  give  only  an  examination  and  the  dental  work  is  done 
by  an  outside  dentist.  Some  give  examinations  and  clean  the 
teeth  and  some  not  only  give  examinations  but  the  additional 
services  of  cleaning,  filling,  extraction,  bridge,  crown  and  plate 
work.  Some  even  go  so  far  as  to  give  free  dental  services  to 
the  children  of  employees.  In  other  industries  dental  work 
is  not  free  but  at  the  employee's  expense  although  it  may  be 
done  in  the  company's  time.  In  still  other  industries  where 
physical  examinations  are  given  by  physicians,  an  arrange- 
ment is  made  with  an  outside  dentist  or  dispensary  to  do  the 
dental  work  for  the  industry  at  a  reduced  cost. 

The  description  of  the  dental  clinic  at  the  home  office  of  the 
Metropolitan  Life  Insurance  Company  as  described  by  Dr. 
Lee  K.  Frankel,  is  very  interesting  and  instructive.  (Taken 
from  "Industrial  Medicine  and  Surgery"  by  Harry  E. 
Mock.) 

The  clinic  Avas  opened  July  1,  1915.  The  equipment  was  the  best  ob- 
tainable.    It  included : 

Four  S.  S.  White-Evans-Forsythe  Dental  Units,  which  consist  of 
chair,  bracket,  engine,  cuspidor,  and  compressed  air  attaeliment. 

Four  S.  S.  White  Lyons  operating  stools. 

Four  electric  spray  heaters. 

One  Eitter  Columbia  dental  chair. 

One  Ritter  dental  engine. 

One  electro-dental  switchboard. 

One  Waugh  radiographic  machine  and  lead  screen. 

Two  sterilizing  outfits. 

Four  small  cabinets. 

One  large  dental  cabinet. 

One  metal  and  glass  linen  cabinet. 

Complete  set  of  instruments;  towels,  bibs,  etc. 


INDUSTRIAL    HYGIENE  317 

It  was  planned  that  the  Avork  should  ]>e  limited  to  a  careful  exami- 
nation and  cleansing  of  the  employees'  teeth  each  six  months.  The  re- 
sults of  the  examination  are  charted  and  copies  of  the  charts  are  given 
to  the  employees,  indicating  what  subsequent  treatment  will  be  necessary 
by  their  own  dentists. 

A  follow-up  system  was  inaugurated  to  ascertain  whether  the  neces- 
sary attention  is  given.  No  attempt  was  made  to  require  or  compel 
employees  to  come  to  the  clinic.  From  time  to  time  addresses  were  de- 
livered by  the  dentists  in  charge  to  the  employees,  indicating  the  value 
of  proper  care  of  the  teeth. 

There  are  approximately  5,000  employees  in  the  company 's  service 
at  the  home  office;  2870  treatments  were  given  to  2707  patients  in  the 
first  six  months,  July  1,  1915  to  December  20,  1915.  In  the  second  six 
months  3383  treatments  were  given  to  2843  patients.  In  the  first  six 
months  the  average  time  required  for  examination  and  cleansing  was 
approximately  sixty-six  minutes.  With  the  experience  gained  by  the 
dentists  in  charge,  this  was  reduced  so  that  in  the  second  six  months  the 
average  time  was  forty-nine  minutes.  The  average  time  required  is  con- 
stantly decreasing.  Viewed  mouth  by  month  this  is  shown  very  clearly. 
In  January  1916^  the  average  time  was  sixty-three  minutes,  in  February 
fifty-four  minutes,  in  March  fifty-three  minutes,  in  April  forty-eight  min- 
utes, in  May  forty-seven  minutes,  and  in  June  thirty-five  minutes. 

The  clinic  is  in  charge  of  Dr.  Thaddeus  P.  Hyatt,  who  has  under  him 
four  assistants  and  a  radiographer.  Seven  women  are  employed  in  the 
dental  clinic  as  assistants  to  the  dentists,  as  telephone  operators,  in  the 
sterilizing  room,  etc.  All  the  dentists  are  full-time  employees  with  the 
exception  of  Dr.  Hyatt.  The  service  given  to  the  employees  is  free  and 
on  the  company's  time. 

I  am  giving  you,  herewith,  the  statistics  for  the  second  six  months, 
namely;  Jan.  1,  1916  to  June  30,  1916,  as  these  are  probably  more  in- 
dicative than  would  be  those  in  the  first  six  months  of  the  service.  In 
this  time  prophylactic  treatment  was  given  to  2315  patients  and  emer- 
gency care  to  528  additional  patients,  making  a  total  of  2843  patients 
cared  for  in  the  period.  The  average  time  for  emergency  cases  twenty- 
one  and  one-half  minutes.  Under  this  term  is  included:  treatment  for 
abscess,  pyorrhea,  exposed  pulp,  gingivitis,  pulpitis,  pericementitis,  in- 
fected tooth  socket,  toothache,  and  extractions  and  consultations. 

The  cost  of  the  entire  service  was  $7,229,  or  an  average  of  $3.00  per 
hour,  and  an  average  per  patient  of  $2.33.  Subdividing  the  prophylactic 
work  from  the  emergency  work,  the  cost  per  patient  for  the  former  was 
$2.46  and  for  the  emergency  work  the  cost  per  patient  was  $1.06.  As- 
suming that  employees  accept  service  of  this  kind  each  six  months,  the 


318  HYGIENE:     DENTAL    AND    GENERAL 

cost  per  treatment  per  patient  per  annum  wonld,  of  course,  be  double 
the  figure  given  per  employee  treated. 

The  results  even  this  far  obtained  are  of  considerable  interest :  of  the 
clerks  who  appeared  in  the  first  six  months,  1636  who  showed  cavities  on 
the  first  examination  reappeared  during-  the  second  six  months.  These 
clerks  on  the  original  examination  had  7,753  cavities  or  an  average  of 
4.6  cavities  per  person.  During  the  interval  between  the  first  and  second 
examination  916  clerks  (56  per  cent)  out  of  the  1637  who  had  cavities 
had  2936  fillings  made,  or  an  average  of  3.2  fillings  per  clerk. 

There  are  other  evidences  of  improvement  although  they  are  not  of 
such  importance.  At  the  time  of  the  first  examination  3.9  per  cent  of 
the  clerks  did  not  use  a  toothbrush.  At  the  second  examination  it  was 
found  that  this  had  been  reduced  to  2.9  per  cent.  At  the  time  of  the 
first  examination  32.9  per  cent  of  the  clerks  did  not  show  clean  mouths. 
At  the  second  examination  only  22.5  per  cent  showed  such  condition. 

The  dentist  must  realize  keenly  any  special  dangers  to  the 
teeth  which  may  be  inherent  in  the  various  processes  of  tlie 
industry,  and  it  is  his  duty  by  both  prophylaxis  and  education 
to  safeguard  the  worker's  health  in  this  respect.  Frequently 
an  employee  reports  to  the  hospital  with  what  he  believes  to 
be  an  industrial  disease  when  in  reality  he  is  suffering  from 
systemic  effects  arising  from  decayed  or  abscessed  teeth  which 
may  or  may  not  have  a  relationship  to  the  industrial  process 
in  which  he  is  engaged. 

Disease  Prevention  and  Health  Education. — Every  member 
of  the  medical  department-  should  appreciate  the  value  and 
saving  of  disease  prevention.  And  this  activity  must  have 
the  hearty  support  of  the  men  in  the  industry  if  it  is  to  be 
successful.  Just  as  75  per  cent  of  accident  prevention  de- 
pends upon  the  Safety  Organization  of  the  workers,  so  health 
is  acquired,  maintained  or  lost  by  the  individual.  Health  is 
like  salvation;  no  one  can  secure  yours  for  you.  Health 
education  in  industry  should  not  be  built  from  the  top  down 
but  from  the  bottom  up.  The  general  manager  cannot  limit 
preventable  disease  but  the  willing  cooperation  of  the  workers 
can  do  it.  The  health  expert  in  industry  who  can  interest 
and  organize  the  men  and  women  of  the  factory  for  health 
betterment  both  in  the  shop  and  in  the  community  will  ac- 


INDUSTRIAL    HYGIENE  319 

complish  more  than  a  reduction  in  the  morbidity  rate.  For 
after  all  life  is  not  a  matter  of  the  pay  envelope  and  the 
more  men  and  women  of  the  industrial  class  are  interested  in 
the  conditions  of  the  home,  the  conditions  of  labor,  the 
liealth  and  welfare  of  their  families  and  their  fellow  men,  the 
more  efficient  will  be  our  industries,  the  more  stable  our  popu- 
lation, and  the  more  intelligent  our  government. 

INDUSTRIAL   DISEASES 

The  dentist  should  know  the  industrial  diseases  which  have 
mouth  lesions  and  the  industries  in  which  they  occur.  In  the 
ease  of  those  industrial  poisons  which  like  acids  hasten  the 
decay  of  teeth,  it  will  naturally''  be  the  part  of  a  dentist  em- 
ployed in  an  establishment  to  prevent  the  injurious  effects  of 
the  harmful  substance  by  keeping  a  careful  and  continual 
watch  over  the  dental  conditions  of  the  men  in  that  branch  of 
tlie  industry  and  by  prophylaxis  and  instruction  to  teach 
them  to  avoid  the  dangers  incident  to  their  work.  We  shall 
briefl}'  discuss  the  important  industrial  diseases  which  have 
mouth  lesions ;  but  the  dentist  who  is  working  over  people  em- 
l^loyed  in  trades  where  any  one  of  the  industrial  diseases 
exists  would  want  to  consult  the  references  and  study  such 
diseases  in  much  greater  detail. 

Lead  Poisoning'. — Lead  is  a  common  cause  of  serious  poison- 
ing. It  is  not  readily  eliminated  from  the  body  and  even 
small  amounts  which  are  swallowed  or  absorbed  through  the 
respiratory  tract  or  the  skin  soon  accumulate  in  serious  quan- 
tity. One  of  the  early  symptoms  of  lead  poisoning  which  may 
be  seen  even  before  serious  physical  defects  are  noticed  is  the 
blue  line  on  the  gums.  This  is  usuallj^  a  double  line:  a  line 
upon  the  teeth  just  below  the  gum  which  may  be  removed  by 
washing  and  another  line  upon  the  gums  themselves  and  con- 
sisting of  lead  sulphite  which  has  been  thrown  down  at  this 
point.  The  susceptibility  to  lead  poisoning  varies  and  young 
adults  are  most  susceptible,  women  being  more  susceptible 
than  men. 


320  HYGIENE  :     DENTAL    AND    GENERAL 

Lead  is  poisonous  in  almost  any  form  although  the  soluble 
salts  like  the  carbonates  are  more  dangerous  than  the  in- 
soluble salts  like  the  sulphates.  For  this  reason,  lead  carbon- 
ate is  eliminated  from  industries  wherever  possible.  The  most 
common  methods  of  poisoning  by  lead  are  by  the  inhaling  of 
lead  dust,  or  by  swallowing  lead  which  is  carried  to  the  mouth 
in  various  ways  by  the  hands.  Absorption  of  the  soluble  lead 
salts  through  the  skin  may  take  place  but  this  type  of  poison- 
ing is  relatively  unimportant. 

Other  symptoms  of  lead  poisoning  include  restriction  of 
the  secretion  of  saliva,  a  sweetish  taste  in  the  mouth,  weak- 
ness, weak  pulse,  constipation,  high  blood  pressure  and  anemia. 
Later  developments  may  include  wrist  drop  and  encephalitis, 
which  appears  as  an  acute  insanity.  This  poisoning  is  par- 
ticularly dangerous  where  women  are  employed. 

Phosphorus  Poisoning-. — A  serious  disease  resulting  from 
phosphorus  poisoning  is  known  as  "phossy  jaw."  There  is 
an  extremely  painful  inflammation  of  the  jaw  bone  in  the 
early  stages  which  later  becomes  chronic  and  produces  a  local- 
ized degeneration  of  the  bone.  The  phosphorus  produces 
either  a  septic  gingivitis  by  inflaming  the  gums  or  an  active 
inflammation  by  acting  through  decayed  teeth.  In  either  case 
there  is  soon  pus  formation  in  the  swollen  gum  and  the  pain- 
ful jaw  bone.  There  are  two  kinds  of  phosphorus ;  the  white 
or  yellow  which  is  highly  poisonous  and  the  red  or  amorphous 
which  is  practically  nonpoisonous. 

Phosphorus  poisoning  was  most  common  in  the  match  in- 
dustry but  the  modified  methods  of  making  matches  have  for- 
tunately nearly  eliminated  the  disease.  In  place  of  the  old- 
fashioned  phosphorus  match  we  have  a  match  made  with  the 
nonpoisonous  sesqui-sulphid  of  phosphorus.  The  "safety 
match"  contains  potassium  chlorate  or  chromate  with  other 
oxygenous  substances  and  is  scratched  on  a  special  surface 
which  contains  antimony  sulphid  and  red  phosphorus.  Phos- 
phorus poisoning  still  occurs  where  certain  special  processes 
— like  the  manufacture  of  bone  black,  phosphates  or  rat  pois- 
ons— are  carried  on. 


Industrial  hygiene  32l 

Mercury  Poisoning' — The  indications  of  mercurial  poison- 
ing are  ulcerations  of  the  gums,  loosening  of  the  teeth,  pain 
and  swelling  in  the  salivary  glands,  headache,  anemia,  tremor 
of  the  muscles,  depleted  breath  and  dizziness.  Frequently  the 
molar  teeth  are  lost  and  the  other  teeth  are  black  and  eroded 
from  the  acid  solution. 

Mercury  is  absorbed  through  the  respiratory  system,  the 
skin  or  the  digestive  system.  Edsall  has  cited  cases  in  dent- 
ists who  had  the  habit  of  working  their  amalgam  in  the  palm 
of  the  hand  and  thus  absorbed  mercury  through  the  skin. 
Poisonings  most  frequently  occur  from  the  amalgam  used  in 
separating  gold  and  silver  ore  and  from  the  mercuric  nitrates 
used  in    the  fur  dressing  industry. 

Benzene  Compounds. — Among  the  other  substances  which 
produce  mouth  lesions  may  be  included  benzene  which  some- 
times produces  a  chronic  poisoning  with  pupuric  hemorrhage 
of  the  mucous  membranes  of  the  mouth  and  throat.  Aniline 
and  nitro-benzene  both  produce  a  definite  cyanosis  of  the  lips 
and  face  usually  spoken  of  as  the  "blues."  These  and  other 
benzene  compounds  produce  serious  effects  upon  the  nervous 
system.  The  poisons  do  not  affect  the  teeth,  but  they  might 
be  detected  in  the  dental  practise  and  referred  to  a  physician. 

Acids. — The  metallic  acids  are  used  in  many  industries  and 
unless  suitable  care  is  taken  they  produce  serious  effects  by 
dissolving  the  dentine  of  the  teeth.  Hydrochloric,  sulphuric 
and  hydrofluoric  acids  are  the  most  common  offenders.  Pic- 
ric acid  in  addition  to  its  injurious  effects  upon  the  teeth  pro- 
duces an  inflammation  of  the  mucous  membrane  of  the  mouth. 

Protection  Ag^ainst  Industrial  Poison. — It  has  been  seen 
that  some  industrial  poisons  are  given  a  greater  opportunity 
to  act  where  defective  teeth  arc  present,  but  in  addition  to 
putting  the  teeth  in  first  class  condition  there  are  other 
measures  of  precaution  which  need  to  be  taken  to  protect  the 
the  industrial  worker.  These  include  proper  instruction  con- 
cerning the  nature  of  the  industrial  hazards,  the  installation 


322  HYGIENE:     DENTAL   AND   GENERAL 

of  suitable  ventilation  to  remove  dust  and  fumes,  the  instal- 
lation of  wet  processes  for  dry  and  dusty  ones  where  possi- 
ble, the  use  of  proper  protective  clothing,  and  the  liberal  use 
of  washing  facilities  which  should  be  adequate  for  the  working 
force.  For  a  consideration  of  these  matters,  the  reader  must 
consult  a  more  extensive  work  on  the  subject  of  Industrial 
Hygiene. 


CHAPTER  XVI 

VENTILATION,  HEATING  AND  LIGHTING 

The  ventilation,  heating  and  lighting  of  a  man's  place  of 
work  and  his  home  directly  affect  his  health  and  the  health 
and  comfort  of  his  family.  The  professional  man  often  fails 
to  realize  that  the  poor  ventilation  and  lighting  of  his  office 
increases  both  the  discomfort  and  the  irritability  of  his  pa- 
tients or  guests.  Everyone  at  some  time  or  other  has  felt 
the  oppressiveness  of  the  air  upon  entering  a  poorly  ventilated 
room.  We  are  sensitive  to  certain  changes  of  temperatures 
and  barometric  conditions.  We  appreciate  the  unusual  fa- 
tiguing eft'eet  of  a  day 's  work  in  an  office  when  the  ventilation 
is  poor,  and  we  have  high  regard  for  the  stimulating  effect  of 
outdoor  life  at  the  seaside  or  in  the  moutains  during  the  sum- 
mer. Everybody  knows  that  there  is  a  difference  between 
good  air  and  bad,  but  too  few  people  know  in  what  that  dif- 
ference consists  and  still  fewer  people  have  the  energy  and 
courage  to  insist  upon  suitable  ventilation  in  office,  home  or 
public  buildings. 

GOOD  AIR  DEFINED 

The  old  idea  that  the  quality  of  air  is  determined  by  its 
chemical  characteristics  has  been  found  to  be  wrong.  As  chil- 
dren most  of  us  were  taught  that  bad  air  was  air  poor  in 
oxygen  and  loaded  with  carbon  dioxide.  It  was  thought  that 
poor  air  must  contain  too  little  oxygen  to  supply  the  demands 
of  the  body,  and  that  carbon  dioxide  acted  as  a  body  poison. 
Recent  physiological  experiments  have  shown  that,  contrary 
to  the  former  belief,  it  is  the  physical  and  not  the  chemical 
character  of  the  air  which  determines  its  quality.  A  compar- 
ison of  the  oxygen  and  carbon  dioxide  contents  of  outdoor  air, 
exhaled  air,  and  the  air  of  poorly  ventilated  rooms  shows  the 
reasonableness  of  the  discovery. 

323 


324  HYGIENE:     DENTAL   AND    GENERAL 

Oxygen  and  Carbon  Dioxide  Content  of  Different  Kinds  of  Air. 

.    Oxygen  Carbon  dioxide 

Composition  of  pure  air 21%  .04% 

Air  in  the  lungs 16%  5.00% 

The  air  in  the  worst  ventilated  rooms.  .  .19%  .40% 
Composition  of  air  which  chemically  pro- 
duces physiological  injury 14%  3.00% 

It  is  to  be  noted  that  there  is  a  wide  difference  between 
"close  air"  and  air  which  produces  injury  by  virtue  of  its 
chemical  composition.  Even  in  the  worst  ventilated  room  the 
air  is  chemically  much  better  than  that  in  the  lungs. 

Until  very  recently  little  attention  was  paid  to  the  effect  of 
air  upon  the  skin,  although  now  we  recognize  it  as  most  impor- 
tant. It  is  hard  to  believe  that  the  soft  free  air  can  make  us 
uncomfortable  by  its  contact  with  a  thick  tough  structure 
like  the  skin  until  we  realize  that  our  skin  not  only  receives 
the  external  contact  stimuli  but  also  helps  to  regulate  the  body 
temperature  as  it  is  acted  upon  by  the  air  from  without  and 
the  nervous  system  from  within. 

It  is  easy  to  forget  that  the  skin  is  a  sense  organ,  for  unless 
we  are  either  chilled  or  perspiring  other  more  important 
thoughts  and  stimuli  crowd  these  minor  sensations  into  ob- 
livion. It  is  like  the  ticking  of  a  clock  to  which  we  have  be- 
come accustomed.  We  work  in  the  room  and  are  not  conscious 
that  the  clock  is  present  and  yet  if  it  stops  we  are  immediately 
aware  of  it. 

The  movement  of  air  against  the  body  produces  definite 
sensations  as  it  is  easy  to  demonstrate.  Step  from  the  breezy 
porch  of  your  summer  cottage  into  a  room  with  the  doors 
and  windows  closed  so  that  there  is  no  movement  of  the  air. 
Sit  for  a  few  minutes  quietly  and  then  return  to  the  porch 
and  see  if  the  breezes  do  not  have  a  pleasing  and  stimulating 
effect.  The  deadening  effect  inside  the  room  was  due  to  the 
fact  that  the  air  immediately  about  the  body,  the  aerial 
dlanket,  was  not  being  rapidly  changed.  There  was  very 
slight  movement  of  air  in  the  room  and  the  clothes  held  this 


VENTILATION,    HEATING    AND    LIGHTING  325 

"blanket"  closely  wrapped  around  the  body.  If  we  go  out 
from  a  warm  room  in  winter  weather  we  notice  a  definite  and 
marked  reaction  of  the  skin.  Similar  but  lesser  reactions  are 
continually  taking  place  in  adjusting  the  body  to  the  chang- 
ing condition  of  air  and  no  doubt  the  body  receives  an  im- 
portant stimulation  from  this  gentle  playing  upon  the  nerv- 
ous system  by  the  changing  air. 

These  considerations  are  in  harmony  with  the  results  of  ex- 
periments conducted  by  the  New  York  A^entilating  Commis- 
sion and  by  other  investigators.  For  example,  a  man  is  put  in 
a  closed  box  where  the  air  is  hot  and  moist.  A  feeling  of  dis- 
comfort soon  develops  which  cannot  be  relieved  by  feeding  the 
man  air  from  the  outside  by  means  of  a  tube  passed  through 
the  wall  of  the  box.  The  sjonptoms  of  discomfort  are  relieved 
by  turning  on  an  electric  fan  inside  the  box,  even  when  the 
subject  breathes  the  air  from  within  which  has  been  vitiated 
by  continuous  breathing.  On  the  other  hand,  a  man  sitting 
outside  the  box  in  air  of  proper  temperature  and  humidity 
is  not  injuriously  affected  by  breathing  through  a  tube  which 
supplies  him  with  air  from  within  even  though  it  is  vitiated, 
hot  and  moist.     The  effect  is  on  the  skin  not  on  the  lungs. 

Experiments  have  failed  to  demonstrate  the  presence  of  any 
injurious  organic  substance  or  "crowd  poison"  in  breathed 
air  although  it  has  been  found  that  disagreeable  odors  pro- 
duce a  depressing  effect  upon  the  appetite. 

We  deduct  from  the  foregoing  statement  that  the  most 
important  problem  in  ventilation  is  a  suitable  change  of  the 
aerial  blanket,  and  that  moving  air  of  the  proper  tempera- 
ture and  humidity,  the  wearing  of  clothes  which  allow  rea- 
sonable ventilation  to  the  skin,  and  the  use  of  water  and  air 
baths  to  keep  the  skin  clean,  are  the  primary  considerations. 
The  important  considerations  in  air  supply  are  a  comfortable 
temperature  and  a  suitable  humidity.  It  is  indeed  foolish 
for  fresh  air  cranks  to  advise  poor  people  to  suffer  with  the 
cold  because  they  "need  to  have  the  windows  open  to  secure 
fresh  air." 


326  HYGIENE:     DENTAL   AND   GENERAL 

Temperature. — If  we  examine  the  effect  of  different  tem- 
peratures upon  the  body,  we  find  that  if  the  temperature  is 
between  80°  and  100°  F.  the  body  adjusts  its  heat-regulating 
mechanism  so  that  it  just  keeps  pace  with  the  loss  of  heat 
from  the  body  by  the  evaporation  of  perspiration  and  by  heat 
transfer,  (i.  e.,  radiation  and  conduction).  The  optimum  tem- 
perature is  68°  F.  Slight  variations  from  this  temperature 
will  not  quickly  call  the  heat-regulating  mechanism  into  op- 
eration so  that  discomfort  may  be  felt  between  60°  and  75° 
because  it  is  neither  so  warm  as  to  start  active  perspiration 
nor  so  cold  as  to  require  active  movement.  If  the  temperature 
is  below  65°  and  above  40°  such  a  chilliness  is  felt  that  if 
the  person  is  free  to  do  so  he  will  move  about  and  thereb}^ 
increase  the  body  temperature  by  greater  oxidation.  It  has 
been  suggested  that  the  feeling  of  discomfort  arises  from  the 
difficulty  which  the  heat-regulating  mechanism  is  experienc- 
ing. 

Moisture. — What  effect  does  the  varying  moisture  content 
of  the  air  have  upon  the  body?  We  know  that  water  is  a 
good  conductor  of  heat  and  therefore  if  the  air  is  moist  and 
cold  it  will  seem  very  chilly  because  the  heat  is  conducted 
away  from  the  body  rapidly,  even  though  the  skin  has  re- 
acted tc  the  low  temperature  and  reduced  the  evaporation 
of  moisture.  On  the  other  hand,  if  the  day  is  very  hot  and 
the  air  is  moist  the  evaporation  of  perspiration  will  be  less 
rapid  because  the  air  is  already  loaded  with  moisture.  This 
prevents  the  body  from  cooling  itself  by  the  process  of  evap- 
oration. It  thus  appears  that  a  moist  air  seems  colder  at  35° 
and  warmer  at  95°  than  dry  air  at  the  same  temperatures. 
In  either  case  an  increase  in  the  movement  of  the  air  would 
make  it  seem  colder  or  cooler  because  moving  air  continually 
changes  the  aerial  blanket  and  increases  heat  transfer  and 
evaporation. 

Odors. — We  have  said  that  disagreeable  odors  are  injurious 
to  health  in  having  a  definite  effect  upon  the  appetite.     They 


VENTILATION,    HEATING    AND    LIGHTING 


327 


probably  also  irritate  or  depress  the  nervous  system.  To  be 
sure  the  olfactory  nerve  soon  becomes  tired  and  insensible  to 
a  given  odor  but  the  depressing  effect  no  doubt  continues. 

The  nose  can  always  detect  a  new  odor  or  a  different  odor 
and  for  this  reason  the  odor  of  the  air  is  a  good  index  of  its 
freshness  or  staleness  when  one  first  enters  the  room.  Odors 
arise  from  foul  breath,  an  unclean  mouth,  decayed  teeth,  ca- 
tarrh, the  sudoriferous  glands  from  the  feet  and  axillas,  and 
from  the  decomposition  of  organic  matter  on  the  skin  and 
clothes.  Moisture  is  always  necessary  for  the  detection  of 
odors  and  they  therefore  become  more  objectionable  as  the 


Fig.    49. — Wet   and  dry   bulb   thermometer  for   wall   attachment.      (Courtesy   of   the 
Taylor  Instrument  Companies,  Rochester,  N.   Y.) 

air  becomes  more  humid.  Sometimes  heat  or  a  draft  of  com- 
pressed air  will  remove  odors  from  solid  surfaces  where  mere 
ventilation  will  not. 

Testing'  Air. — The  air  in  living  rooms  which  is  not  being 
changed  with  sufficient  frequency  is  likely  to  be  odorous  and 
it  is  not  difficult  to  detect  this  with  the  senses  upon  entering 
a  close  or  stuffy  room.  The  test  for  the  amount  of  carbon 
dioxide  in  the  air  will  also  indicate  whether  the  air  is  fresh 
or  used.  The  temperature  may  be  read  directly  from  a  ther- 
mometer. 


328 


HYGIENE :     DENTAL   AND    GENERAL 


But  we  must  know  the  relative  humidity  of  air  as  well  as 
its  temperature  in  order  to  know  whether  it  is  properly  con- 
ditioned for  the  body.  Relative  liumidity  is  expressed  in 
terms  of  per  cent  saturation.  When  the  air  is  completely 
saturated  with  moisture  we  have  a  mist  or  fog.  At  68°  F. 
the  optimum  humidity  is  about  50  per  cent. 

The  body  is  sensitive  to  the  dryness  of  the  air  because  the 
drier  the  air  the  greater  the  evaporation  of  moisture.  It  is 
this  principle  that  is  used  in  determining  relative  humidity. 
If  the  bulb  of  an  ordinary  thermometer  is  wrapped  in  a  moist 
cloth,  evaporation  will  take  place  from  the  cloth  and  the 
thermometer  will  be  cooled,  registering  a  lower  temperature 


Fig.    SO. — Sling    psychrometer.       (Courtesy    of    the    Taylor    Instrument    Companies, 

Rochester,  N.  Y.) 


than  the  ordinary  thermometer  in  the  same  room.  The  drier 
the  air,  the  greater  the  rate  of  evaporation,  the  greater  will  be 
the  difference  between  the  dry  bulb  and  wet  bulb  readings. 
The  movement  of  air  also  affects  the  rate  of  evaporation ;  but 
evaporation  approaches  its  maximum  rate  when  the  air  is  mov- 
ing at  about  four  miles  per  hour,  so  that  if  the  wet  bulb 
thermometer  is  swung  in  the  air  with  a  free  arm  motion  the 
minimum  reading  can  be  obtained  in  a  few  moments, 


VENTILATION',    HEATING   AND   LIGHTING  320 

The  Sling"  Psychrometer. — An  instrument  in  common  use 
for  testing  the  dryness  of  air  is  the  sling  psychrometer  which 
consists  of  a  dry  bulb  thermometer  and  a  wet  bulb  thermom- 
eter attached  to  a  solid  frame  which  can  be  rotated  in  the  air. 
The  instrument  is  swung  until  the  minimum  reading  is  ob- 
tained on  the  wet  bulb  thermometer  and  the  relative  humidity 
is  obtained  by  comparing  the  difference  in  temperatures  with 
a  set  of  standard  tables.  From  these  tables  it  is  possible  to 
obtain  the  relative  humidity,  the  number  of  grams  of  moisture 
in  the  air  and  the  dew  point  for  the  air  having  its  dry  and 
wet  bulb  temperatures  recorded. 


Fig.  51. — Hygrodeik  showing  the  chart  from  which  the  condition  of  the  air 
may  be  read  directly.  This  is  the  most  satisfactory  instrument  for  telling  mois- 
ture content  quicklv.  (Courtesy  of  the  Taylor  Instrument  Companies,  Rochester, 
N.  Y.) 

The  HygTodeik. — This  instrument  has  a  dry  and  a  wet 
bulb  thermometer  placed  on  the  two  sides  of  a  graphic  chart 
in  such  a  way  that  the  approximate  percentage  saturation, 
grains  of  water  per  cubic  foot,  and  dew  point  may  be  read 
directly  from  the  chart  by  comparing  the  temperatures  of 
the  two  thermometers.  A  pointer  swings  across  the  chart  be- 
tween the  thermometers  and  the  desired  readings  may  be  ob- 
tained by  placing  it  over  the  intersection  of  the  two  lines 
which  connect  the  thermometer  readings. 


330  HYGIENE :     DENTAL   AND   GENERAL 

The  Polymeter. — Various  instruments  are  made  which  indi- 
cate roughly  the  relative  humidity  by  showing  the  effect  of 
moisture  in  contracting  or  expanding  some  substance  like 
horse  hairs.  The  horse  hair  is  usually  run  from  the  top  of 
the  instrument  to  a  shaft  connecting  with  a  dial  at  the  base. 
If  these  instruments  are  kept  in  proper  condition  the  dial 
will  roughly  indicate  the  amount  of  moisture  in  the  air,  that 
is,  with  an  accuracy  of  perhaps  1°  to  5°.  But  in  order  that 
they  remain  in  good  condition  they  should  be  dipped  in  water 
every  day  or  at  least  every  few  days. 

The  Comfort  Meter. — Dr.  Hill  has  developed  a  new  instru- 
ment for  indicating  the  quality  of  the  air  which  does  away 
with  the  difficulty  of  trying  to  combine  the  two  factors  of 
temperature  and  humidity.  This  is  a  spirit  thermometer 
graduated  from  95°  to  100°  F.  It  is  heated  to  100°  and  the 
time  taken  to  fall  to  95°  is  registered.  Without  moisture  this 
thermometer  records  of  the  effect  of  the  temperature  and 
motion  of  the  air;  when  a  cloth  saturated  with  water  is 
wrapped  around  the  bulb  it  also  takes  account  of  the  effect 
of  humidity.  It  will  be  seen  that  this  instrument  when  mois- 
tened at  100°  F.  closely  simulates  the  body,  and  the  cooling 
effect  of  the  air  upon  a  moist  warm  body  at  any  temperature 
can  thus  be  readily  determined.  The  instrument  is  calibrated 
and  the  constant  factor  is  written  upon  the  back.  By  divid- 
ing the  time  in  seconds  by  the  constant  factor,  one  obtains  the 
loss  of  heat  per  square  centimeter  per  second  in  terms  of 
milli-calories.  The  wet  bulb  should  show  not  less  than  18 
milli-calories  per  second  and  the  dry  bulb  not  less  than  6. 

VENTILATING  AND  HEATING 

The  problem  of  ventilation  is  to  supply  clean  air,  free  from 
bacteria  and  dust,  at  the  proper  temperature  and  with  the 
suitable  amount  of  moisture.  To  ventilate  we  must  renew 
the  air  in  a  room  but  in  order  to  secure  air  which  is  properly 
conditioned  we  must  often  heat  or  cool,  and  moisten  or  dry 
the  air  in  addition. 


VENTILATION,    HEATING    AND    LIGHTING  331 

Merely  because  we  have  assigned  new  causes  for  the  dis- 
agreeable effects  which  have  always  been  recognized  as  the 
result  of  poor  air,  we  must  not  forget  that  these  ill  effects 
still  persist.  Properly  conditioned  air  must  always  be  sup- 
plied and  in  a  suitable  quantity  and  standards  of  air  space 
in  different  kinds  of  workrooms  are  still  useful,  although  we 
should  remember  that  the  rate  of  change  of  air  is  more  im- 
portant than  the  size  of  the  w^orkroom. 

The  standards  set  by  a  committee  of  the  American  Society 
of  Heating  and  Ventilation  in  1915,  prescribe  for  a  theatre, 
a  floor  space  per  person  of  6  square  feet,  a  cubic  space  of  90 
cubic  feet,  and  an  air  spply  of  1,200  cubic  feet  per  hour.  In 
a  workshop  the  floor  space  should  be  increased  usually  to  25 
square  feet,  the  cubic  space  to  250  cubic  feet,  and  the  hourly 
air  supply  to  1,500  cubic  feet  per  person  (the  amount  of  air 
required  for  an  ordinary  gas  burner).  The  air  should  be  of 
a  temperature  between  60°  and  72°  F.  The  distribution 
should  maintain  the  proper  temperature  without  uncomfort- 
able drafts  or  any  draft  lower  than  60°  F.  For  temperatures 
above  55°  F.  the  most  comfortable  percentage  humidity  may 
be  obtained  from  the  formula  R  =  316  -  4T,  where  T  ==  the 
temperature  of  the  room  and  E  =  the  corresponding  relative 
humidity. 

The  air  should  be  free  from  unpleasant  odors  and  reason- 
ably free  from  dust  which  of  itself  is  more  or  less  irritating 
and  is  usually  germ  laden.  Mechanical  exhaust  systems  are 
needed  in  many  workrooms  to  keep  the  air  free  from  dust, 
while  air  washing  is  necessary  in  some  localities  to  secure  a 
satisfactory  supply. 

Natural  Ventilation. — Ventilation  may  be  either  natural  or 
artificial.  By  natural  ventilation  we  mean  the  replacing  of 
air  inside  a  building  by  the  outside  air  which  works  its  way 
of  its  own  accord  through  the  wall  and  through  openings  to 
the  outside.  Even  solid  walls  allow  for  the  passage  of  a  good 
deal  of  air  and  much  more  enters  through  open  windows, 
ventilating  flues,  or  chimneys,  cracks  or  crevices  in  the  walls. 


332  HYGIENE:     DENTAL   AND    GENERAL 

under  doors  and  around  windows.  There  are  numerous  me- 
chanical appliances  which  furnish  openings  through  walls 
or  windows  and  assist  in  the  interchanging  of  inside  and  out- 
side air.  Sometimes  this  exchange  of  air  is  assisted  by  aspirat- 
ing or  withdrawing  the  air  from  within  by  means  of  the 
natural  draft  of  a  flue  or  chimney  augmented  by  a  heater. 
The  amount  of  leakage  of  air  in  a  building  depends  on  the 
ratio  of  the  cubic  contents  of  the  building  to  the  exposed  sur- 
face, the  tightness  of  doors,  windows,  etc.,  and  the  condition 
of  the  walls.  In  general  it  is  assumed  that  the  leakage  amounts 
to  one  change  of  air  per  hour.  That  is,  an  amount  of  air 
equal  to  the  cubical  contents  of  a  frame  building  will  pass 
through  the  walls  each  hour  and  an  equal  volume  of  air  must 
be  heated  to  replace  the  loss.  The  air  will  oftentimes  be 
changed  two  times  per  hour  by  spontaneous  ventilation. 

The  size  of  the  room  as  well  as  the  number  of  people  in  the 
room  influences  the  rate  at  which  the  air  should  be  changed. 
The  number  of  changes  of  air  which  take  place  under  direct 
heating  in  buildings  is  given  below. 

NUMBEE  OF  TIMES  AIE  CHANGES  PER  HOUR 

Residences  Halls  3;  sitting-rooms  2 

Stores  First  story  2  to  3;   2nd  story  1^2  to  2 

Offices  First  story  2  to  21/2;  2nd  story  li^  to  2 
Churches  and  Halls        %  to  2 
Large  rooms  with 

small  exposure  %  to  1 

Artificial  or  Mechanical  Ventilation. — For  large  buildings 
such  as  halls,  churches,  business  establishments  and  factories, 
the  change  of  air  through  natural  processes  is  not  sufficient 
and  some  mechanical  system  of  ventilation  is  adopted.  This 
may  be  one  of  three  types:  (1)  the  exhaust  or  vacuum  sys- 
tem by  which  air  is  withdrawn  from  the  room  by  means  of 
suction  fans,  (2)  the  plenum  system  by  which  air  is  forced 
into  the  room  by  fans  or  (3)  the  comhmed  method  which 
forcibly  brings  air  into  the  room  and  forcibly  exhausts  it, 
combining  both  of  the  above  systems. 


VENTILATION,    HEATING   AND   LIGHTING  333 

There  are  various  ways  of  introducing  and  removing  air 
from  a  room,  but  in  general  it  may  be  said  that  in  buildings 
of  moderate  size  such  as  residences,  office-buildings,  school- 
rooms and  factories,  where  the  building  is  cut  up  into  rooms 
not  over  fifty  feet  square,  the  intake  ducts  should  be  in  the 
side  walls  near  the  top  of  the  room  from  eight  to  ten  feet 
above  the  floor  and  should  discharge  the  air  with  a  velocity 
not  exceeding  6  feet  per  second  so  that  the  drafts  will  not  be 
felt.  Exit  ducts  should  be  in  the  side  walls  near  the  floor. 
By  bringing  the  heated  air  in  at  the  top  of  the  room  its 
velocity  is  gradually  dissipated  and  by  the  time  the  incoming 
air  has  descended  to  the  breathing  level  no  draft  should  be 
felt.  The  opening  of  a  register  should  be  from  0.66  to  0.75  of 
the  area  of  the  opening  in  the  duct  into  which  the  register  fits. 

In  modern  factories  the  air  is  heated  to  a  temperature  of 
from  90° -140°  and  is  forced  into  the  building  by  fans.  This 
air  after  supplying  wall  losses  by  its  loss  in  temperature  is 
taken  back  to  the  fan  at  60° -70°  and  is  then  drawn  through 
the  heater,  heated  again  to  the  higher  temperature  and  forced 
back  into  the  factory.  The  air  in  the  factory  is  thus  put  un- 
der a  slight  pressure  and  any  leakage  of  air  is  outward, 
therefore  a  small  amount  of  outside  air  must  be  constantly 
added  before  the  air  passes  through  the  heater. 

There  are  various  ways  of  distributing  the  air  sent  in  by 
the  fans.  The  most  common  method  is  by  ducts  located  from 
8  to  18  feet  above  the  floor.  It  is  also  done  by  means  of 
hollow  pilasters  in  the  sides  of  the  long  distributing  ducts 
which  extend  the  entire  length  of  the  building.  The  velocity 
of  the  discharged  air  varies  from  3  to  50  feet  per  second 
depending  on  the  size  of  the  room.  Where  there  are  numer- 
ous outlets  and  low  velocities,  the  combined  area  of  the  air 
inlets  should  exceed  the  discharge  area  of  the  fan  by  25  per 
cent. 

The  Importance  of  Moisture. — It  may  be  demonstrated 
that  tlie  air  in  a  room  at  65°  F.  and  50-55%  relative  humidity, 
actually  feels  warmer  than  that  of  a  room  which  is  maintained 


334  HYGIENE  :     DENTAL    AND    GENERAL 

at  70-75°  F.  and  30%  relative  humidity.  This  is  due  to  the 
fact  that  the  sensation  of  heat  or  cold  felt  by  the  body,  or 
the  "sensible  temperature"  is  not  indicated  by  the  tempera- 
ture of  the  dry  bulb  thermometer,  but  more  closely  cor- 
responds to  the  temperature  indicated  by  the  wet  bulb  ther- 
mometer. From  this  it  is  evident  that  a  higher  temperature 
is  maintained  in  our  buildings  than  would  be  required  if  ar- 
rangements were  made  for  maintaining  the  proper  relative 
humidity. 

If  a  room  feels  cold  at  68°  F.  it  is  because  the  humidity 
is  too  low.  The  amount  of  moisture  a  cubic  foot  of  air  will 
hold  depends  entirely  upon  the  temperature.  The  lower  the 
temperature  of  the  air,  the  less  moisture  it  is  capable  of 
holding.  Air  at  70°  F.  will,  if  saturated,  hold  8  grains  of 
moisture  per  cubic  foot.  Air  at  0°  F.  will  hold  practically 
0.48  grains  per  cubic  foot  at  saturation.  The  average  rela- 
tive humidity  during  winter  is  about  70%  ;  hence  air  at  0°  F. 
and  70%  relative  humidity  contains  0.34  grains  of  moisture 
per  cubic  foot.  If  this  air  is  drawn  from  outdoors  into  a 
building  and  heated  to  70°  F.  the  absolute  humidity  or  the 
weight  of  moisture  per  cubic  foot  will  remain  the  same  as  be- 
fore, but  the  relative  humidity  is  now  reduced  to  about  4%. 
Such  air  is  drier  than  that  of  the  most  arid  region. 

Dry  furnace  air  is  therefore  likely  to  cause  excessive  evap- 
oration and  give  one  a  chilly  feeling.  For  living  rooms 
and  offices  the  humidity  may  be  increased  by  plants,  or  by 
porous  dishes,  like  flower-pots,  containing  water  or  by  plac- 
ing a  dish  of  water  or  a  wet  towel  on  or  near  the  radiator. 
It  is  evident  that  fuel  can  be  saved  by  maintaining  air  of  a 
reasonably  high  humidity. 

Air  Washing-  and  Humidifying-. — Although  the  humidity 
may  be  secured  by  simple  devices  in  small  rooms,  more  in- 
tensive methods  must  be  used  for  large  buildings.  The  types 
of  air-washers  and  humidifiers  in  ordinary  use  are  the  "moist 
sheet";  "film  of  water";  and  the  "spray  or  rain"  types. 
These  are  all  modifications  of  one  another  and  in  all  the 
water  is  forced  through  small  openings  in  pipes  so  that  a 


VENTILATION,    HEATING    AND    LIGHTING  335 

slieet  of  water  is  formed,  through  which  the  air  must  pass. 
The  water  is  discharged  through  perforated  pipes  extending 
across  the  top  of  chambers,  these  pipes  discharging  against  a 
deflector. 

In  the  general  method  of  washing  and  conditioning  air  it 
is  first  drawn  through  the  washer  by  means  of  a  fan.  The 
water  carried  mechanically  by  the  air  is  separated  by  means 
of  eliminator  plates;  then  the  saturated  air  is  heated  by 
heater-coils  to  the  desired  temperature.  By  regulating  the 
temperature  of  the  saturated  air  entering  the  heater,  the  hu- 
midity of  the  heated  air  may  be  made  any  desired  amount. 
By  the  use  of  by-passes  under  the  heating  coils,  mixing  damp- 
ers, thermostats,  etc.,  it  is  possible  to  supply  a  constant  vol- 
ume of  pure  air  to  the  rooms  and  to  regulate  the  humidity  of 
this  air.  Tempering  coils  are  important  where  the  incoming 
air  is  apt  to  go  below  32°  F.  especially  where  all  the  air 
handled  is  taken  from  out  of  doors. 

The  washing  of  air  is  often  almost  as  important  as  the  hu- 
midifying. It  is  necessary  to  use  the  outside  air  for  ventila- 
tion and  this  air  is  taken  from  the  lower  levels  where  the 
amounts  of  dust,  bacteria,  and  noxious  gases  are  most  concen- 
trated. Whipple  has  shown  that  when  street  air  is  passed 
through  a  washer  it  requires  but  a  few  hours  for  the  water 
to  become  like  sewage  in  appearance  and  analysis.  Air  drawn 
from  the  rooms,  purified  and  reheated  is  up  to  all  standards 
and  the  cost  of  fuel  necessary  to  heat  the  air  is  considerably 
reduced. 

Cooling  Air. — To  cool  air  and  at  the  same  time  to  reduce 
the  amount  of  moisture,  it  becomes  necessary  to  work  with 
water  at  a  temperature  lower  than  can  ordinarily  be  obtained 
from  eitlier  driven  wells  or  from  city  mains.  Air  cooled  by 
ice  is  unsatisfactory  as  it  is  difficult  to  cool  it  sufficiently  to 
deposit  the  excess  moisture  and  the  slightly  cooled  air  is  likely 
to  have  a  high  relative  Inimidity. 

The  only  satisfactory  method  of  air  cooling  is  by  the  use 
of  refrigerating  machines,  such  as  ammonia  compression  or 
absorption  machines  by  which   the  temperature  may  be  re- 


336  HYGIENE:     DENTAL   AND    GENERAL 

duced  enough  to  cause  a  precipitation  of  the  excess  of  mois- 
ture contained  in  the  air.  When  air  is  cooled  by  this  method 
a  fan  draws  the  air  from  the  room  and  sends  it  through  a 
sheet  of  cold  brine  which  is  continually  cooled  by  an  ammonia 
outfit.  This  brine  is  sprayed  into  the  air  as  is  the  water  in 
an  air  washing  machine. 

In  other  cases  the  air  may  be  sent  through  a  cooler  con- 
taining the  coils  of  an  ammonia  machine.  To  keep  the  coils 
from  becoming  covered  with  frost,  brine  is  allowed  to  trickle 
over  them.  This  brine  washes  the  air  to  some  extent.  It 
is  very  important  that  the  brine  be  of  sufficient  strength  to 
prevent  freezing. 

Air  taken  in  from  the  room  may  be  cooled,  de-humidified 
and  sent  back  or  some  of  the  outside  air  of  higher  temperature 
and  humidity  may  be  mixed  with  cooled  air  in  proper  pro- 
portion to  give  the  final  temperature  and  humidity  desired. 
In  general  it  is  necessary  to  cool  air  to  45°  or  50°  in  order  to 
get  rid  of  the  excess  moisture,  and  it  is  then  necessary  to 
heat  this  air  again  to  70°.  The  hot  moist  air  on  its  way  from 
the  room  to  the  cooler  may  be  made  to  transfer  some  of  its 
heat  to  the  cold,  de-humidified  air  on  its  way  back  to  the  room. 

The  Economic  Value  of  Good  Ventilation. — Industries  have 
found  that  it  is  particularly  important  to  remove  dust,  gases 
and  fumes  which  irritate  the  breathing  passages  of  the  worker 
and  cause  congestion  or  predispose  the  individual  to  infectious 
diseases.  But  even  where  dusts  are  not  present  the  proper 
regulation  of  temperature  and  humidity  has  an  important 
bearing  upon  health  and  efficiency.  Dr.  Winslow  has  shown 
that  under  the  same  conditions  of  work  6  per  cent  more  type- 
writing is  performed  at  68°  than  at  75°.  In  more  vigorous 
physical  work  such  as  ordinary  industrial  activities,  the 
amount  accomplished  at  68°  is  15%  greater  than  that  accom- 
plished at  75°.  In  the  work  of  the  New  York  Commission  on 
Ventilation  it  was  shown  that  the  respiratory  diseases  among 
school  children  in  a  group  of  rooms  averaging  69°  in  tempera- 
ture were  50  per  cent  in  excess  of  similar  respiratory  diseases 
among  groups  of  children  from  school  rooms  whose  tempera- 


VENTILATION,    HEATING    AND    LIGHTING  337 

tures  averaged  only  66°.  It  is  a  cardinal  rule  that  the  tem- 
perature of  living  and  work  places  should  never  exceed  68° 
and  with  proper  humidity  a  healthy  individual  will  not  be 
uncomfortable  at  this  temperature.  Each  work  room  should 
have  a  thermometer  and  some  arrangement  should  occasion- 
ally be  made  to  determine  the  humidity. 

Physicians  feel  that  out  of  door  air  is  better  than  inside 
air  for  invalids  and  consumptives,  even  though  the  inside  air 
is  properly  conditioned.  This  benefit  from  being  out  of  doors 
may  be  due  to  sunlight  or  it  may  be  due  to  the  constantly 
varying  temperature  of  the  outdoor  air  which  doubtless  serves 
as  a  stimulus  and  tonic  to  the  system. 

LIGHTING 

Good  lighting  is  important  in  a  variety  of  ways.  Direct 
sunlight  is  a  disinfectant  and  it  has  been  found  to  increase  the 
peripheral  lymphocytosis  in  the  body.  Its  value  in  treating 
tuberculosis  of  the  skin,  for  example,  has  been  well  demon- 
strated. It  should  be  allowed  to  enter  the  home  and  the  work 
place  as  much  as  possible  but  it  should  be  prevented  from 
shining  directly  in  the  face  of  the  worker. 

Outdoor  life  is  the  normal  condition  to  which  man  has  be- 
come accustomed  throughout  the  process  of  evolution.  Under 
these  conditions  the  light  comes  from  a  luminous  body  above 
^d  very  little  light  is  reflected  from  the  green  or  brown  of 
the  earth,  so  that  the  upper  part  of  the  retina  is  not  accus- 
tomed to  a  strong  stimulation.  If  the  person  looks  up  at  the 
sun  directly  the  stimulation  is  excessive  and  painful.  This 
suggests  the  ideal  condition  for  artificial  lighting.  Strong 
light  should  not  be  thrown  directly  into  the  eyes  from  below. 

Man  has  acquired  great  power  in  adjusting  the  eyes  to  the 
effects  of  bright  daylight  and  darkness.  This  is  done  by 
varying  the  size  of  the  pupil  through  the  muscular  contrac- 
tion of  the  iris.  Flickering  light  causes  the  eye  to  attempt  a 
rapid  series  of  these  adjustments,  a  continual  contraction  and 
expansion  of  this  muscle  resulting  in  eye  strain,  nervousness 
and  fatigue. 


338  HYGIENE:     DENTAL   AND    GENERAL 

Ideal  lighting  provides  sufficient  and  steady  illumination 
at  the  point  of  work  and  the  lighting  should  be  judged  not  by 
the  brightness  of  the  lamps  but  by  the  illumination  at  the 
point  where  the  work  is  done.  Dark  objects  require  more  il- 
lumination than  light  objects. 

Office  Lighting". — Ample  window  space  is  usuallj^  provided 
in  front  of  the  dentist's  chair  but  sufficient  care  is  not  always 
taken  to  provide  adequate  means  of  regulating  the  lighting 
under  different  weather  conditions  bv  means  of  shades  and 


Fig.  52. — A   foot  candlemeter  which  is  portable  and  easy  to  use  in  measuring  light 
intensities.      (Courtesy  of  the  National   Lamp   Works,   Cleveland,    Ohio.) 

• 

curtains.  These  should  be  so  arranged  that  they  can  be  made 
to  cover  either  the  lower  or  the  upper  part  of  the  windows  and 
should  be  of  light  green  or  yellow  material. 

The  artificial  lighting  should  be  indirect  in  order  to  avoid 
glare  either  in  the  eyes  of  the  operator  or  the  patient.  In- 
direct lighting  may  be  provided  by  the  use  of  translucent 
material  or  by  a  reflector  throwing  the  light  up  to  the  ceiling. 
Much  light  is  lost  by  the  latter  type  of  lighting  however  and 
more  efficiency  can  be  secured  by  the  use  of  a  ridged  glass 
which  splits  and  divides  the  rays  of  light.  In  any  case  the 
artificial  light  should  be  steady  and  not  flickering. 


APPENDIX  A 

THE  CONTROL  OF  COMMUNICABLE  DISEASES 

Report    of    The    American    Public    Health    Association 

Committee  on  Standard  Regulations,  Appointed 

IN  October,  1916.* 

In  the  following  report  the  terms  used  are  first  defined. 
Each  disease  is  briefly  described  with  regard  to  the  infective 
agent,  the  source  of  infection,  the  mode  of  transmission,  the 
incubation  period,  and  the  period  of  communicability.  Fol- 
lowing this  are  given  the  methods  of  control — first,  those  affect- 
ing the  individual  patient  and  his  immediate  environment, 
and  second,  general  measures  bearing  upon  the  control  or 
prevention  of  the  disease  in  question. 

Inasmuch  as  the  laws  under  which  various  boards  and  de- 
partments of  health  operate  require  differences  in  the  legal 
phraseology  of  rules,  regulations,  or  sections  of  sanitary  codes 
dealing  with  the  control  of  communicable  diseases  the  com- 
mittee has  refrained  from  preparing  formal  regulations  under 
each  disease.  As  the  report  is  at  present  submitted  any  health 
officer,  board  of  health,  or  legislative  body  having  the  power 
to  make  rules  or  regulations  or  pass  sections  of  sanitary  codes 
dealing  with  the  control  of  communicable  diseases  can,  by 
reference  to  the  description  of  the  disease  and  recommenda- 
tions for  methods  of  control  herewith  proposed,  easily  prepare 
the  necessary  text  upon  which  the  educational  and  adminis- 
trative acts  of  the  health  officer  will  be  based.  The  list  of 
diseases  considered  by  the  committee  and  herewith  reported 
upon  includes  those  given  in  the  Pnhlic  Health  Reports,  Vol. 
30,  No.  27,  July  2,  1915,  of  the  Public  Health  Service  in  ''A 
Model  State  Law  for  Morbidity  Reports." 

*Reprint  from  the  PuliHc  Health  Reports,  vol.  32.  Xo.  41.  Oct.  12,  191",  pp. 
1706-173j.      Used   with   permission    of   the    American    Public    Health   Assn. 

339 


340  HYGIENE:     DENTAL   AND   GENERAL 

The  committee  is  indebted  for  expert  oi^iuion  and  critical 
comment  upon  its  tentative  conclusions  to  Dr.  Simon  Flexner, 
Dr.  William  H.  Park,  Prof.  Theobald  Smith,,  and  Dr.  Bertram 
H.  "Waters,  and  acknowledgment  of  their  contributions  to  the 
report  in  its  present  form  is  herewith  gratefully  expressed. 

Dr.  Haven  Emerson,  Chairman. 
Egbert  N.  Hoyt. 
Dr.  F.  M.  Meader. 
Dr.  J.  C.  Perry." 

C.    E.    A.    WiNSLOW. 

List  of  Diseases 

Actinomycosis.  Paratyphoid  fever. 

Acute  infectious  conjunctivitis.  Plague. 

Anehylostomiasis    (hookworm).  Pneumonia    (acute   lobar). 

Anthrax.  Poliomyelitis. 

Cerebrospinal       meningitis  (epi-       Eabies. 

demic).  Eocky    Mountain    spotted    or    tick 

Chicken  pox.  fever. 

Cholera.  Scarlet  fever. 

Dengue.  Septic  sore  throat. 

Diphtheria.  Smallpox. 

Dysentery  (amebic).  Syphilis. 

Dysentery   (bacillary).  Tetanus. 

Favus.  Trachoma. 

German  measles.  Trichinosis. 

Glanders.  Tuberculosis  (pulmonary). 

Gonorrhea.  Tuberculosis    (other  than  pulnion- 

Leprosy.  ary). 

Malaria.  Typhoid  fever.    . 

Measles.  Typhus  fever. 

Mumps.  Whooping  cough. 

Yellow  fever. 

The  committee  adopted  the  following  definitions  of  terms : 

1.  Carrier. — A  person  who,  without  symptoms  of  a  communicable 
disease,  harbors  and  disseminates  the  specific  microorganisms. 

2.  Cleaning. — This  term  signifies  the  removal,  by  scrubbing  and  wash- 
ing, of  organic  matter  on  which  and  in  which  bacteria  may  find  favor- 
able conditions  for  prolonging  life  and  virulence  j  also  the  removal  by 
the  same  means  of  bacteria  adherent  to  surfaces. 


THE    CONTROL    OF    COMMUNICABLE   DISEASES  341 

3.  Contact. — A  "contact"  is  any  person  or  animal  known  to.  have 
been  sufficiently  near  to  a  human  infected  person  or  animal  to  have  been 
exposed  to  transfer  of  infectious  material  directly,  or  by  articles  freshly 
soiled  with  such  material. 

4.  Delousin-ff. — By  delousing  is  meant  the  process  by  which  a  person 
and  his  personal  apparel  are  treated  so  that  neither  the  adults  nor  the 
eggs  of  Pediculus  corporis  or  Pediculus  capitis  survive. 

.  5.  Disinfection. — By  this  is  meant  the  destroying  of  the  vitality  of 
pathogenic  microorganisms  by  chemical  or  physical  means. 

When  the  word  concurrent  is  used  as  qualifying  disinfection,  it  in- 
dicates the  application  of  disinfection  immediately  after  the  discharge 
from  the  body  of  an  infected  person,  of  infectious  material,  or  the  soil- 
ing of  articles  with  such  infectious  discharges. 

When  the  word  terminal  is  used  as  qualifying  disinfection,  it  indicates 
the  process  of  rendering  the  personal  clothing  and  immediate  physical 
environment  of  the  patient  free  from  the  possibility  of  conveying  the 
infection  to  others,  at  the  time  when  the  patient  is  no  longer  a  source  of 
infection. 

6.  Education  in.  personal  cleanliness. — By  this  phrase  it  is  intended 
to  include  all  the  various  means  available  to  impress  upon  all  members 
of  the  community,  young  and  old,  and  especially  wlien  communicable 
disease  is  prevalent  or  during  epidemics,  by  spoken  and  printed  word, 
and  by  illustration  and  suggestion,  the  necessity  of: 

(1)  Washing  the  body  daily  with  soap  and  water. 

(2)  Washing  hands  in  soap  and  water  after  voiding  bowels  or  Ijladdcr 
and  always  before  eating. 

(3)  Keeping  hands  and  unclean  articles,  or  articles  which  have  been 
used  for  toilet  purposes  by  others  away  from  mouth,  nose,  eyes,  ears,  and 
vagina. 

(4)  Avoiding  the  use  of  common  or  unclean  eating,  drinking,  or 
toilet  articles  of  any  kind,  such  as  towels,  handkerchiefs,  hair  brushes, 
drinking  cups,  pipes,  etc. 

(5)  Avoiding  direct  exposure  to  the  spray  from  the  noses  and  moutlis 
of  people  who  cough  or  sneeze,  or  laugh  and  talk  loudly,  with  wide  open 
mouth,  or  in  explosive  manner. 

7.  Fumigation.* — By  fumigation  is  iiioant  a  process  by  whicli  the 
destruction  of  insects,  as  mosquitoes  and  body  lice,  and  aninuils,  as  rats, 
is  accomplished  by  the  employment  of  gaseous  agents. 


*Author's  Note:  This  dclinitiuu  of  fumigation  applies  throughout  the  follow- 
ing report  and  was  doubtless  arbitrarily  adopted  because  fumigation  is  no  longer 
regarded  as  eft'ective  for  killing  tlie  germs  of  disease.  Fumigation  is  still  imder- 
stood  by  the  general  public,  however,  as  an  attempt  at  disinfection  by  means  of 
a  gas. 


342  HYGIENE:     DENTAL    AND    GENERAL. 

8.  Isolation.^ — ^By  isolation  is  meant  the  separating  of  persons  suf- 
fering from  communicable  disease,  or  carriers  of  the  infecting  organ- 
ism, from  other  persons,  in  such  places  and  under  such  conditions  as  will 
prevent  the  direct  or  indirect  conveyance  of  the  infectious  agent  to  sus- 
ceptible persons. 

9.  Quarantine." — By  quarantine  is  meant  the  limitation  of  freedom 
of  movement  of  persons  or  animals  who  have  been  exposed  to  commu- 
nicable disease  for  a  period  of  time  ec[ual  to  the  incubation  period  of  the 
disease  to  which  they  have  been  exposed. 

10.  Eenovation. — By  renovation  is  meant,  in  addition  to  cleansing, 
such  treatment  of  the  walls,  floors,  and  ceilings  of  rooms  or  houses  as 
may  be  necessary  to  place  the  premises  in  a  satisfactory  sanitary  condi- 
tion. 

11.  Beport  of  a  disease. — By  report  of  a  disease  is  meant  the  notifi- 
cation to  the  health  authorities,  and,  in  the  case  of  communicable  disease 
in  animals,  also  to  the  respective  departments  of  agriculture  Avho  have 
immediate  jurisdiction,  that  a  case  of  communicable  disease  exists  in  a 
specified  person  or  animal  at  a  given  address. 

12.  Susceptiiles.— A  susee]3tible  is  a  person  or  animal  who  is  not 
known  to  have  become  immune  to  the  particular  communicable  disease 
in  question  by  natural  or  artificial  process. 

The  items  considered  necessary  for  presentation  by  tlie 
committee  with  regard  to  each  disease  are  the  following: 

1.  Infective  agent. 

2.  Source  of  infection. 

3.  Mode  of  transmission. 

4.  Incubation  period. 

5.  Period  of  communieability. 
C.  Methods  of  control. 

(A)  The  infected  individual  and  his  environment: 

1.  Recognition  of  the  disease. 

2.  Isolation. 

3.  Immunization. 

4.  Quarantine. 

5.  Concurrent  disinfection. 

6.  Terminal  disinfection. 

(B)  General  measures. 

(C)  Epidemic  measures    (occasionally  require  separate   mention). 


*In  view  of  the  various  ambiguous  and  inaccurate  uses  to  wliich  the  words 
isolation  and  quarantine  are  not  infrequently  put,  it  has  seemed  best  to  adopt 
arbitrarily  the  word  isolation  as  describing  the  limitation  put  upon  the  movements 
of  the  known  sick  or  "carrier"  individual  or  animal,  and  the  word  quarantine  the 
limitations   put    upon    exposed    or    "contact"    individuals    or    persons. 


THE    CONTROL    OF    COMMUNICABLE    DISEASES  343 

Actinomycosis 

1.  Infective  agent:     Actinomyces  bovis. 

2.  Source  of  infection:     The   nasal  and   bowel  diseliarges,   and  the   in- 

fected material  from  lesions  in  human  and  animal  cases  of  the 
disease.  Uncooked  meat  from  infected  animals  may  serve  as  a 
source  of  infection. 

3.  Mode  of  transmission:  By  contact  with  the  discharges  or  with  articles 

freshly  soiled  with  the  discharges  from  animal  or  human  cases. 

4.  Inciihation  ^period:  Unknown. 

5.  Period  of  communicaMUty :     As  long  as  open  lesions  remain,  as  proved 

by  the  presence  of  the  infective  agent  on  microscopic  or  cultural 
tests. 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his   environment — 

1.  Eecognition     of     the     disease — Clinical     symptoms,     con- 

firmed by  microscopic  examination  of  discharges  from 
tlie  lesions. 

2.  Isolation — None,  provided  the  patient  is  under  adequate 

medical  supervision. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Of  discharges  from  lesions  and 

articles  soiled  therewith. 

6.  Terminal  disinfection — By  thorough  cleaning. 

(B)  General  measures — 

1.  Inspection   of  meat,   with   condemnation  of   carcasses,   or 

infected  parts  of  carcasses,  of  infected  animals. 

2.  Destruction   of  known   animal   sources   of  infection. 

Acute  Infectious  Conjunctivitis 

(Not  including  trachoma) 
(This  title  to  replace   the  terms   gonorrheal    ophthalmia,   ophthalmia 
neonatorum,  and  babies'  sore  eyes.) 

1.  Infectious   agent:   The   gonococcus   ur   some   member   of   a   group    of 

pyogenic  organisms,  including  the  licmoglobiuophilic  bacilli. 

2.  Source  of  infection:  Discharges  from  eonjunetiva\  or  adnoxa,  or  geni- 

tal mucous  membranes  of  infected  persons. 

3.  Modes  of  transmission:   Contact  with  an  infected  person  or  with  ar- 

ticles freshly  soiled  with  discharges  of  such  person. 


344  HYGIENE  :     DENTAL    AND    GENERAL 

4.  InmCbation  'period:  Irregular,  but  usually  36  to  48  hours. 

5.  Period  of  coinmunicahility:  During  the  course  of  the  disease  and  until 

the  discharges  from  the  infected  mucous  membranes  have  ceased. 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

■where  possible   by   bacteriological   examination. 

2.  Isolation — None,  provided  the  patient  is  under  adequate 

medical  supervision. 

3.  Immunization — None. 

4.  Quarantine— None. 

5.  Concurrent  disinfection — Disinfection  of  conjunctival  dis- 

charges and  articles  soiled  thereAvith. 

6.  Terminal  disinfection — Thorough  cleansing. 

(B)  General  measures — 

1.  Enforcement   of  regulations   forbidding  the  use  of   com- 

mon  towels  and   toilet   articles.     Education   as   to   per- 
sonal cleanliness. 

2.  Use  of  silver  nitrate  or  some  similar  solution  in  the  eyes 

of  the  new  born. 

Anchylostomiasis 

(Hookworm) 

1.  Infectious  -agent. — Anchylostoma  (Necator  amei'icanus) . 

2.  Source  of  infection. — Feces  of  infested  persons.     Infection  generally 

takes  place  through  the  skin,  occasionally  by  the  mouth. 

3.  Mode  of  transmission. — The  larval  forms  pierce  the  skin,  usually  of 

the  foot,  and  passing  through  the  lymphatics  to  the  vena  cava  and 
the  right  heart,  thence  in  the  blood  stream  to  the  lungs,  they  pierce 
the  capillary  walls  and  pass  into  the  alveoli.  Then  they  pass  up  the 
bronchi  and  trachea  to  the  throat,  whence  they  are  swallowed  and 
finally  lodge  in  the  small  intestine.  Also  by  drinking  water  contain- 
ing larvae,  by  eating  soiled  food,  by  hand  to  mouth  transmission  of 
the  eggs  or  larvas  from  objects  soiled  with  infected  discharges. 

4.  Incuhation  period. — Seven  to  10  weeks. 

5.  Period  of  communicahility. — As  long  as  the  parasite  or  its  ova  are 

found  in  the  bowel  discharges  of  an  infected  individual.  Contami- 
nated soil  remains  infective  for  five  months  in  the  absence  of  freez- 
ing. 

6.  Methods  of  control: 

(A)   The  infected  individual  and  his  environment — 

1.  Eecognition   of  the  disease — Microscopic   examination   ol 
bowel  discharges. 


THE    CONTROL   OF    COMMUNICABLE   DISEASES  345 

2.  Isolation — None. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Sanitary  disposal  of  bowel  dis- 

discharges. 

6.  Terminal  disinfection — None. 

7.  Treatment — Appropriate  treatment  of  infected  individual 

to  rid  the  intestinal  canal  of  the  parasite  and  its  ova. 
(B)   General  measures — 

1.  Education  as  to  dangers  of  soil  pollution. 

2.  Prevention   of   soil  pollution  by  installation   of   sanitary 

disposal  systems  for  human  discharges. 

3.  Personal  prophylaxis  by  cleanliness  and  the  wearing   of 

shoes. 

Anthrax 

1.  Infectious  agent. — Bacillus  anthracis. 

2.  Source  of  infection. — Hair,  hides,  flesh,  and  feces  of  infected  animals. 
3    Mode  of  transmission. — Inoculation  as  by  accidental  wound  or  scratch, 

inhalation  of  spores  of  the  infectious  agent,  and  ingestion  of  in- 
sufficiently cooked  infected  meat. 

i.  Inculcation  period. — Within  seven  days. 

5.  Period  of  communicability. — ^During  the  febrile  stage  of  the  disease 
and  until  lesions  have  ceased  discharging.  Infected  hair  and  hides 
of  infected  animals  may  communicate  the  disease  for  many  months 
after  slaughter  of  the  animal,  and  after  curing  of  hide,  fur,  or  hair, 
unless  disinfected. 

(3.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition     of    the     disease — Clinical     symptoms,     con- 

firmed by  bacteriological  examination. 

2.  Isolation  of  the  infected  individual  until  the  lesions  have 

healed. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent    disinfection    of   the    discharges    from    lesions 

and  articles  soiled  therewith. 
G.  Terminal   disinfection — Tliorough   cleaning. 

(B)  General  measures — 

1.  Animals  ill  with  a  disease  presumably  anthrax  should  be 
placed  immediately  in  the  care  of  a  veterinary  surgeon. 
Proved  animal  cases  of  tlie  disease  should  be  killed 
promptly  and  tlie  caicassos  destroyed,  preferably  by  fire. 


346  HYGIENE:     DENTAL    AND   GENERAL 

2.  Isolation  of  all  animals  affected  with  the  disease. 

3.  Immunization    of    exposed    animals    under    direction    of 

.Federal  or  State  Department  of  Agriculture. 

4.  Postmortem  examinations  should  be  made  only  by  a  vet- 

erinary surgeon,  or  in  the  presence  of  one. 

5.  Milk  from  an  infected  animal  should  not  be  used  during 

the  febrile  period. 

6.  Control   and   disinfection   of   effluents   and   trade   wastes 

and  of  areas  of  land  polluted  by  such  effluents  and 
wastes  from  factories  or  premises,  where  spore-infected 
hides  or  other  infected  hide  and  hair  products  are 
known  to  have  been  worked  up  into  manufactured  ar- 
ticles. 

7.  A    physician    should    be    constantly    employed    by    every 

company  handling  raw  rides,  or  such  companies  should 
operate  under  the  direct  supervision  of  a  medical  rep- 
resentative of  the  health  department. 

8.  Every  employee  handling  raw  hides,  hair,  or  bristles  who 

has  an  abrasion  of  the  skin  should  immediately  report 
to  a  physician. 

9.  Special    instruction    should    be    given    to    all    employees 

handling  raw  hides  in  regard  to  the  necessity  of  per- 
sonal cleanliness. 

10.  Tanneries    and    woolen    mills    should    be    provided    with 

proper  ventilating  apparatus  so  that  dust  can  be 
promptly  removed. 

11.  Disinfection  of  hair,  wool,  and  bristles  of  animals  origi- 

nating in  knoAvn  infected  centers  before  they  are  used 
or  assorted. 

12.  The  sale  of  hides  from  an  animal  infected  with  anthrax 

should  be  prohibited.  A  violation  of  this  regulation 
should  be  immediately  reported  to  the  State  commis- 
sioner of  agriculture,  by  telegram,  stating  the  time, 
place,  and  purchaser  to  whom  the  hide  was  sold.  The 
report  should  also  be  sent  to  the  person  purchasing  the 
hide.  Carcasses  should  be  disposed  of  under  the  super- 
vision of  the  State  department  of  agriculture.  The  in- 
spection and  disinfection  of  imported  hides  are  under 
the  supervision  of  the  United  States  Bureau  of  Animal 
Industry.  In  the  event  that  infection  is  introduced  the 
State  agricultural  authorities  have  jurisdiction  over  in- 
fected animals  and  the  local  or  State  health  authorities 
have  jurisdiction  over  infected  persons. 


THE    CONTROL    OF    COMMUNICABLE    DISEASES  347 

Cerebrospinal  Meningitis 

Infective  agent:   Diplocoeeus  intraeellularis   (the  meningococcus). 

Source  of  infection:  Discharges  from  the  nose  and  mouth  of  infected 
persons..  Clinically  recovered  cases,  and  healthy  persons  who  have 
never  had  the  disease  but  have  been  in  contact  with  cases  of  the  dis- 
ease or  other  carriers,  act  as  carriers  and  are  commonly  found,  es- 
pecially during  epidemics.  Such  healthy  carriers  are  not  uncom- 
monly found  independent  of  epidemic  prevalence  of  the  disease. 

Mode  of  transmission :  By  direct  contact  with  infected  persons  and 
carriers,  and  indirectly  by  contact  with  articles  freshly  soiled  witli 
the  nasal  and  mouth  discharges  of  such  persons. 

Incubation  period:  Two  to  ten  days,  commonly  seven.  Occasionally 
for  longer  periods  when  a  person  is  a  carrier  for  a  time  before  de- 
veloping the  disease. 

Period  of  commumcahility :  During  the  clinical  course  of  the  disease 
and  until  the  specific  organism  is  no  longer  present  in  the  nasal  and 
mouth  discharges  of  the  patient.  The  same  applies  to  healthy  car- 
riers so  far  as  affects  persistence  of  infectious  discharges. 

Metlwds  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

by  the  microscopic  and  bacteriological  examination  of 
the  spinal  fluid,  and  by  bacteriological  examination  of 
nasal  and  pharyngeal  secretions. 

2.  Isolation  of  infected  persons  and  carriers  until  the  naso- 

pharynx is  free  from  the  infecting  organism,  or,  at  the 
earliest,  until  one  week  after  the  fever  has  subsided. 

3.  Immunization  may  prove  of  value.     Immunization  by  the 

use  of  vaccines  still  in  the  experimental  stage. 

4.  Quarantine — None. 

5.  Concurrent  disinfection  of  discharges  from  the  nose  and 

mouth  and  of  articles  soiled  therewith. 

6.  Terminal  disinfection — Cleaning. 

(B)  General  measures — 

1.  Search  for  carriers  among  families  and  associates  of  rec- 

ognized cases  by  bacteriological  examination  of  pos- 
terior nares  of  all  contacts. 

2.  Education    as    to    personal    cleanliness    and    necessity    of 

avoiding  contact  and  droplet  infection. 

3.  Prevention  of  overcrowding  such  as  is  common  in  living 

quarters,  transportation  conveyances,  working  places, 
and  places  of  pulilic  assemldy  in  the  civilian  population, 
and  in  inadequately  ventilated  closed  quarters  in  bar- 
racks, camps,  and  ships  among  military  units. 


348  HYGIENE :     DENTAL   AND    GENERAL 

Chicken  Pox 

1.  Infectious  agent:     Unknown. 

2.  Source  of  infection -.Hhe  infectious  agent  is  presumably  present  in  the 

lesions  of  the  skin  and  of  the  mucous  membranes;  the  latter  appear- 
ing early  and  rupturing  as  soon  as  they  appear,  render  the  disease 
communicable  early,  that  is,  before  the  exanthem  is  in  evidence. 

3.  Mode   of  transmission:    Directly   from   person   to   person;    indirectly 

through  articles  freshly  soiled  by  discharges  from  an  infected  in- 
dividual. 

4.  Incubation  'period:  Two  to  three  weeks. 

5.  Period  of  communicability :  Until  the  primary  scabs  have  disappeared 

from  the  mucous  membranes  and  the  skin. 

6.  Metlwds  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms.     The  dif- 

ferential diagnosis  of  this  disease  from  smallpox  is  im- 
portant, especially  in  people  over  15  years  of  age. 

2.  Isolation — Exclusion  of  patient  from  school,  and  preven- 

tion of  contact  with  nonimmune  persons. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent   disinfection   of   articles   soiled  by   discharges 

from  lesions. 

6.  Terminal  disinfection — Thorough  cleaning. 

(B)  General  measures — None. 

Cholera 

1.  Infectious  agent:     Vibrio  choleree. 

2.  Source  of  infection:   Bowel  discharges  and  vomitus  of  infected  per- 

sons, and  feces  of  convalescent  or  healthy  carriers.  Ten  per  cent 
of  contacts  may  be  found  to  be  carriers. 

3.  Mode  of  transmission:    By  food  and  water  polluted  by   infectious 

agent;  by  contact  with  infected  persons,  carriers,  or  articles  freshly 
soiled  by  their  discharges;  by  flies. 

4.  Incubation  period:  One  to  five,  usually  three,  days,  occasionally  longer 

if  the  healthy  carrier  stage,  before  develoxnnent  of  symptoms,  is 
included. 

5.  Period  of  communicaMlity :     Usually  7  to  14  days  or  longer  and  until 

the  infectious  organism  is  absent  from  tTie  bowel  discharges. 

6.  Methods  of  control: 

(A)   The  infected  individual  and  his  environment — 

1.  Recognition  of  the  disease — Clinical  symptoms,  confirmed 
by  bacteriological  examination. 


TIIH    CONTROL    OF    COMMUNICABLE    DISEASES  349 

2.  Isolation  of  patient  in  hospital  or  screened  room. 

3.  Immunization  by  vaccination  may  be  of  value. 

4.  Quarantine — Contacts   for   five   days  from  last   exposure, 

or  longer  if  stools  are  found  to  contain  the  cholera 
vibrio. 

5.  Concurrent   disinfection — Prompt  and   thorough  disinfec- 

tion of  the  stools  and  vomited  matter.  Articles  used  by 
and  in  connection  with  the  patient  must  be  disinfected 
before  removal  from  the  room.  Food  left  by  the  pa- 
tient should  be  burned. 

6.  Terminal  disinfection — Bodies  of  those  dying  from  chol- 

era should  be  cremated  if  practicable,  or,  otherwise, 
wrapped  in  a  sheet  wet  with  disinfectant  solution  and 
placed  in  water-tight  caskets.  The  room  in  which  a 
sick  patient  was  isolated  should  be  thoroughly  cleaned 
and  disinfected. 
(B)   General  measures — 

1.  Eigid  personal  prophylaxis   of  attendants  by  scrupulous 

cleanliness,  disinfection  of  hands  each  time  after  han- 
dling patient  or  touching  articles  contaminated  by  de- 
jecta, the  avoidance  of  eating  or  drinking  anything  in 
the  room  of  the  patient,  and  the  prohibition  of  those 
attendant  on  the  sick  from  entering  the  kitchen. 

2.  The  bacteriological  examination  of  the  stools  of  all  con- 

tacts to  determine  carriers.     Isolation  of  carriers. 

3.  Water  should  be   boiled,   if   used  for   drinking   or  toilet 

purposes,  or  if  used  in  washing  dishes  or  food  containers, 
unless  the  water  supply  is  adequately  protected  against 
contamination  or  is  so  treated,  as  by  chlorination,  that 
the  cholera  vibrio  can  not  survive  in  it. 

4.  Careful  supervision  of  food  and  drink.     Where  cholera  is 

prevalent,  only  cooked  foods  should  be  used.     Food  and 
drink    after    cooking    or    boiling    should    be    protected 
against  contamination,  as  by  flics  and  human  handling. 
(C)   Epidemic  measures — 

Inspection  service  for  early  detection  and  isolation  of  cases; 
examination  of  persons  exposed  in  infected  centers  for 
detection  of  carriers,  Avith  isolation  or  control  of  car- 
riers; disinfection  of  rooms  occupied  by  the  sick,  and 
the  detention,  in  suitable  camps  for  five  days,  of  those 
desirous,  of  leaving  for  another  locality.  Those  so  de- 
tained should  be  examined  for  detection  of  carriers. 


350  HYGIENE:     DENTAL    AND   GENERAL 

Dengue 

1.  Infectious  agent:  Unknown. 

2.  Source  of  infection:  The  blood  of  infected  persons. 

3.  Mode  of  transmission:  By  the  bite  of  infected  mosquitoes,  probably 

Aedes  calopus  (perhaps  also  Culex  fatigans). 

4.  Incubation  period:  Four  to  five  days. 

5.  Period  of  communicahility :   During  the  febrile  stage  of  the  disease. 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Recognition  of  the   disease — Clinical   symptoms. 

2.  Isolation — The  patient  must  be  kept  in  a  screened  room. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — None. 

6.  Terminal    disinfection — None.     Upon   termination   of   the 

case,  fumigation  of  the  room  and  house,  to  destroy  mos- 
quitoes. 

(B)  General  measures — 

Measures  directed  toward  elimination  of  mosquitoes.  Screen- 
ing of  rooms. 

Diphtheria 

1.  Infectious  agent:  Bacillus  diphtheriae  (the  Klebs-Loefflor  bacillus). 

2.  Source   of  infection :    Discharges   from   diphtheritic   lesions   of   nose, 

throat,  conjunctiva,  vagina,  and  wound  surfaces.  Secretions  from 
the  nose  and  throat  of  carriers  of  the  bacillus. 

3.  Mode  of  transmission:  Directly  by  personal  contact,  indirectly  by  ar- 

ticles freshly  soiled  with  discharges,  or  through  infected  milk  or 
milk  products. 

4.  Incihbation  period:    Usually  two  to  five   days,   occasionally  longer  if 

a  healthy  carrier  stage  precedes  the  development  of  clinical  symp- 
toms. 

5.  Period  of  communicaiility :     Until  virulent  bacilli  have  disappeared 

from  the  secretions  and  the  lesions.  The  persistence  of  the  bacilli 
after  the  lesions  have  healed  is  variable.  In  fully  three-quarters 
of  the  cases  they  disappear  within  tAvo  weeks.  In  95  per  cent  of 
cases,  the  bacilli  disappear  in  four  weeks.  In  exceptional  cases 
virulent  bacilli  remain  in  the  throat  and  discharges  for  from  two  to 
six  months. 

6.  Methods  of  control : 

(A)   The  infected  individual  and  his  environment — 

1.  Recognition  of  the  disease — By  clinical  symptoms  with 
confirmation  by  bacteriological  examination  of  dis- 
charges. 


THE    CONTROL   OF    COMMUNICABLE   DISEASES  351 

2.  Isolation — Until   two    cultures    from   the   throat    and   two 

from  the  nose,  taken  not  less  than  24  hours  apart,  fail 
to  show  the  presence  of  diphtheria  bacilli.  Isolatiot^  may 
bo  terminated  if  persistent  diphtheria  bacilli  prove 
avirulent.  Where  termination  by  cultuio  is  impracti- 
cable cases  may  be  terminated  with  fair  safety  as  a  rule 
16  days  after  onset  of  the  disease. 

3.  Immunization — Exposed   susceptibles  to  be  promptly   im- 

munized by  antitoxin.  (By  susceptibles  is  meant  such 
individuals  as  are  found  to  be  nonimmune  by  the 
Schick  test,  i.  e.,  those  who  give  a  positive  reaction). 

4.  Quarantine — All  exposed  persons  until  shown  by  bacterio- 

logical examination  not  to  be  carriers. 

5.  Concurient  disinfection  of  all  articles  which  have  been  in 

contact  with  the  patient  and  all  articles  soiled  by  dis- 
charges from  the  patient. 

6.  Terminal  disinfection — At  the  end  of  the  illness,  thorough 

airing  and  sunning  of  the  sick  room,  with  cleaning  or 
renovation. 
(B)   General  measures — 

1.  Pasteurization  of  milk  supply. 

2.  Application   of  the   Schick  test  to  all   contacts,   and  im- 

munization of  all  susceptibles. 

3.  Application  of  the  Schick  test  to  all  children. 

4.  Immunization   by   toxin-antitoxin   inoculation   of   all   sus- 

ceptibles. 

5.  Determination  of  presence  or  absence  of  carriers  among 

contacts,  and,  so  far  as  practicable,  in  the  community 
at  large. 

Dysentery  (Amebic) 

1.  Infectious  agent:   Amcba  histolytica. 

2.  Suurce  of  infection  :   The  bowel  discharges  of  infected  persons. 

3.  Mode  of  transmission:  By  drinking  contaminated  water,  and  by  eat- 

ing infected  foods,  and  by  hand  to  mouth  transfer  of  infected  ma- 
terial; from  objects  soiled  with  discharges  of  an  infected  individual 
or  of  a  carrier;  by  flies. 

4.  Incubation  period:  Unknown. 

5.  Period  of  cominnnicabiUty:    During  course   of   disease   and   until   re- 

peated microscopic  examinaticn  of  stools  sliows  absence  of  Ameba 
histolytica. 


352  HYGIENE:     DENTAL   AND    GENERAL 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

by  microscopic  examination  of  stools. 

2.  Isolation — None. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection  of  the  bowel  discharges.. 

6.  Terminal   disinfection — Cleaning. 

(B)  General  measures — 

1.  Boil  drinking  water  unless  the  supply  is  known  to  be  free 

from  contamination. 

2.  Water  supply  should  be  protected  against  contamination 

and  supervision  should  be  exercised  over  all  foods  eaten 
raw. 

Dysentery  (Bacillary) 

1.  Infectious  agent:  Bacillus  dysenteria3. 

2.  Source  of  infection:  The  bowel  discharges  of  infected  persons. 

.3.  Mode  of  transmission :  By  drinking  contaminated  w.ater,  and  by  eat- 
ing infected  foods,  and  by  hand-to-mouth  transfer  of  infected  ma- 
terial: from  objects  soiled  with  discharges  of  an  infected  individual 
or  of  a  carrier  by  flies. 

4.  Incuiaiion  period:     Two  to  seven  days. 

u.  Period  of  communicu'bility:  During  the  febrile  period  of  the  disease 
and  until  the  organism  is  absent  from  the  bowel  discharges. 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

by  serological  and  bacteriological  tests. 

2.  Isolation — Infected  individuals  during  the  communicable 

period  of  the  disease. 

3.  Immunization — Vaccines     give     considerable     immunity. 

Owing  to  severe  reactions  their  use  is  not  universal,  nor 
should  it  be  made  compulsory  except  under  extreme 
emergency. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Bowel  discharges. 

6.  Terminal  disinfection — Cleaning. 

(B)  General  measures — 

1.  Eigid  personal  prophylaxis  of   attendants  upon  infected 
persons. 


THE    CONTROL    OF    COMMUNICABLE    DISEASES  353 

2.  No  milk  or  food  for  human  consumption  should  be  sold 

from  a  place  occupied  by  a  patient  unless  the  persons 
engaged  therein  occupy  quarters  separate  from  the 
house  where  the  patient  is  sick,  and  all  utensils  used 
are  cleaned  and  kept  in  a  separate  building,  and  under 
a  permit  from  the  health  officer. 

3.  All   attendants   iipon  persons   affected   with   this   disease 

should  be  prohibited  from  having  anything  to  do  with 
the  handling  of  food. 

4.  Necessary  precautions  against  flies. 

Favus 

1.  Infections  agent:  Achorion  schoenleinii. 

2.  Source  of  infeotion:  Lesions  of  skin,  particularly  on  scalp. 

3.  Mode   of   transmission:    Direct   contact   with  patient,   and   indirectly 

through  toilet  articles. 

4.  Inouhation  period:  Unknown. 

5.  Period  of  communicaMUty :  Until  skin  and  scalp  lesions  are  all  healed. 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms  confirmed 

by  microscopic  examination  of  crusts. 

2.  Isolation — Exclusion    of   patient   from   school    and    other 

jiublic  places  until  lesions  are  healed. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent   disinfection — Toilet  articles  of  patient. 

6.  Terminal  disinfection — None. 

(B)  General  measures — 

1.  Elimination  of  common  utensils,  such  as  hair  brushes  and 

combs. 

2.  Provision  for  adequate  and  intensive  treatment  and  cure 

of  cases  of  favus  at  hospitals  and  dispensaries,  to  ab- 
breviate the  period  of  infectivity  of  the  patients. 

German  Measles 

1.  Infectious  agent :  Unknown. 

2.  Source  of  infection  :  Secretions  of  the  mouth  and  possibly  of  the  nose. 

3.  Mode  of  transmission:  By  direct  contact  with  the  patient  or  with  ar- 

ticles freshly  soiled  with  the  discharges  from  the  nose  or  throat  of 
the  patient. 

4.  Incuhation  period:  From  10  to  21  days. 


354  HYGIENE:     DENTAL   AND    GENERAL 

5.  Period  of  communicahiUty:  Eight  days  from  onset  of  the  disease. 

6.  Method  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms. 

2.  Isolation — Separation    of    the    patient    from    nonimmune 

children,  and  exclusion  of  the  patient  from  school  and 
public  places  for  the  period  of  presumed  infectivity. 

3.  Immunization — None. 

4.  Quarantine— None   except   exclusion    of   nonimmune   chil- 

dren from  school  and  public  gatherings,  from  the  elev- 
enth to  the  twenty-second  day  from  date  of  exposure 
to  a  recognized  case. 
5.  Concurrent  disinfection — Discharges  from  the  nose  and 
throat  of  the  patient  and  articles  soiled  by  discharges. 
6.  Terminal  disinfection — Airing  and  cleaning. 

(B)  General  measures — : 

None. 

Note. — The  reason  for  attempting  to  control  this  disease  is  that  it  may  be  con- 
fused with  scarlet  fever  during  its  early  stages;  each  person  having  symptoms  of 
the  disease  should  therefore  be  placed  under  the  care  of  a  physician  and  the  case 
should  be  reported  to  the  local  department  of  health. 

Glanders 

1.  Infectious  agent:   Bacillus  mallei. 

2.  Source  of  infection:   Discharges  from  open  lesions  of  mucous  mem- 

branes, or  of  the  skin  of  human  or  equine  cases  of  the  disease  (i.  e., 
pus  and  mucus  from  the  nose,  throat,  and  bowel  discharges  from 
infected  man.  and  horse). 

3.  Mode  of  transmission:    Contact  with  a  case  or  with  articles  freshly 

soiled  by  discharges  from  a  human  or  equine  case. 

4.  Inctibation  period:  Unknown. 

5.  Period  of  communicability :   Until  Ijacilli  disappear  from   discharges 

or  initil  lesions  have  healed. 

6.  Methods  of  control : 

(A)   The  infected  individual  and  his  environment — 

1.  Eecognition   of   the   disease — By   specific  biological  reac- 

tions, such  as  the  complement  fixation  test,  the  mallein 
test,  the  agglutination  test,  or  by  nonspecific  reactions, 
such  as  the  Straus  reaction,  if  confirmed  by  culture,  or 
by  identification  of  the  Bacillus  mallei,  or  by  autopsy 
of  douljtful  cases. 

2.  Isolation — Human  case  at  home  or  hospital;  for  infected 

horses  destruction  rather  than  isolation  is  advised. 


TlIK    COXTROT.    OF    COM  M  I -NTTCATU,!':    DISEASES  .).);) 

.3.  Iiimumizatiou — Xouc    of    ostalilished    value    or    gonerally 
aeccijtecl. 

4.  Quarantine  of  all  horses  in  an  infected  stable  until  all 

have  heen  tested  by  specific  reaction,  and  the  removal 
of  infected  horses  and  terminal  disinfection  of  stable 
have  been  accomplished. 

5.  Concurrent    disinfection — Disi-haroes    from    Imnian    cases 

and  articles  soiled  thercwitli. 

6.  Terminal    disinfection — Stables    and    contents    wliere    in- 

fected horses  are  found. 
(B)   General  measures — 

1.  The  abolition  of  the  common  drinking  trough  for  horses. 

2.  Sanitary  supervision  of  stables  and  blacksmith  shops. 

3.  Semi-annual  testing  of  all  horses  by  a  specific  reaction 

Tvhere  the  disease  is  common. 

4.  Testing  of  all  horses  offered  for  sale  where  the  disease 

is  common. 

XoTE. — In  this  disease,  as  in  all  infectious  or  communicable  diseases  from 
which  both  animals  and  humans  suffer,  cases  occurring  in  animals  should  be  re- 
jjorted  to  the  Department  of  Agriculture  and  hun-,an  cases  should  be  reported  to 
the  Department  of  Health,  reciprocal  notification  thereafter  to  lie  accomplished 
through    official    interdepartment   channels. 

Gonorrhea 

1.  Infectious  agent:  Gonococcus. 

2.  Source  of  infection:  Discharges  from  lesions  of  inflamed  mucous  mem- 

branes and  glands  of  infected  persons,  viz.,  urethral,  vaginal,  cervi- 
cal, conjunctival  mucous  membranes,  and  Bartholin's  or  Skene's 
glands  in  the  female,  and  Cowper's  and  the  prostate  glands  in  the 
male. 

3.  Mode  of  tmnsmis'Sion:   By  direct  personal  contact  with  infected  per- 

sons, and  indirectly  by  contact  witli  articles  freshly  soiled  with  the 
discharges  of  such  persons. 

4.  Incubation' period:  One  to  eight  days,  usually  three  to  five  days. 

5.  Period  of  communicability,:  As  long  as  the  gonococcus  persists  in  any 

of  the  discharges,  whether  the  infection  be  an  old  or' a  recent  one. 

6.  Mciliods  of  control: 

(A)    The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

by  bacteriological  examination  or  serum  reaction. 

2.  Isolation — When    the    lesions    are    in    the    genitourinary 

tract,  exclusion  from  sexual  contact,  and  when  the 
lesions  are  conjunctival,  exclusion  fi"om  school  or  contact 
with  children,  so  long  as  the  discharges  contain  the  in- 
fecting organism. 


356  HYGIENE  :     DENTAL    AND    GENERAL 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — Discharges  from  lesions  and  ar- 

ticles soiled  therewith. 

6.  Terminal  disinfection — None. 
(B)   General  measures — 

1.  Education  in  matters  of  sexual  hygiene,  particularly  as 

to  the  fact  that  continence  in  both  sexes  at  all  ages 
is  compatible  with  health  and  development. 

2.  Provision  for  accurate  and  early  diagnosis,  and  treatment 

in  hospitals  and  dispensaries  of  infected  persons  with 
consideration  for  privacy  of  record  and  provision  for 
following  cases  until  cured. 

3.  Eepressiori  of   prostitution  by  use   of   police   power   and 

control  of  use  of  living  premises. 

4.  Restriction  of  sale  of  alcoholic  beverages. 

5.  Eestrictions  of   advertising   of  services  or  medicines  for 

the  treatment  of  sex  diseases,  etc. 

6.  Elimination   of   common  towels   and  toilet   articles   from 

public  places. 

7.  Use  of  prophylactic  silver  solution  in  the  eyes  of  the  new 

born. 

8.  Exclusion  of  persons  in   the   communicable  stage  of  the 

disease  from  participation  in  the  preparing  and  serving 
of  food. 

9.  Personal  prophylaxis  should  be  advised  to  those  who  ex- 

pose themselves  to  ojoportunity  for  infection. 

Leprosy 

1.  Infectious  agent:   Bacillus  leprae. 

2.  Source  of  infection:  Discharges  from  lesions. 

3.  Mode  of  transmission:  By  close,  intimate,  and  prolonged  contact  with 

infected  individuals.     Flies   and   other   insects   may   be   mechanical 
carriers. 

4.  Incubation  period:  Prolonged,  undetermined. 

5.  Period  of  communicability :  Infectivity  exists  throughout  the  duration 

of  the  disease.     Where  good  standards  of  personal  hygiene  prevail 
this  disease  is  but  slightly  communicable. 

6.  Methods  of  control: 

(A)   The  infected  individual  and  his  environment — 

1.  Recognition  of  the  disease — Clinical  symptoms,  confirmed 
by  bacteriological  examination. 


THE    CONTROL    OF    COMMUNICABLE    DISEASES  357 

2.  Isolation   for   life   in  national   leprosarium   when   this   is 

possible. 

3.  Immunization — None. 

4.  Quarantine-^— None. 

5.  Concurrent    disinfection — Discharges    and    articles    soiled 

with  discharges. 

6.  Terminal     disinfection — Thorough     cleansing     of     living 

premises  of  the  patient. 
(B)   General  measures — 

1.  Lack   of   information   as   to   the    determining   factors   in 

the  spread  and  communication  of  the  disease  makes  any 
but  general  advice  in  matters  of  personal  hygiene  of  no 
value. 

2.  As  a  temporary  expedient,  lepers  may  be  properly  cared 

for  in  local  hospitals,  or  if  conditions  of  the  patient  and 
his  environment  Avarrant,  he  may  be  allowed  to  remain 
on  his  own  premises  under  suitable  regulations. 

Malaria 

1.  Infectious  agent:   The  several  species  of  malarial  organisms. 

2.  Source  of  infection:   The  blood  of  an  infected  individual. 

3.  Mode  of  transmission:  By  bite  of  the  infected  Anopheles  mosquitoes. 

The  mosquito  is  infected  by  biting  an  individual  suffering  from 
acute  or  chronic  malaria.  The  parasite  develojDS  in  the  body  of 
the  mosquito  for  from  10  to  14  days,  after  which  time  the  sporozoites 
appear  in  its  salivary  glands. 

4.  Incuiatio%  period:   Varies  with  the  type  of  species  of  infecting  or- 

ganism and  the  amount  of  infection;  usually  14  days  in  the  tertian 
variety. 

5.  Period  of  communicahility:  As  long  as  the  malaria  organism  exists  in 

the  blood. 
C.  Methods  of  control : 

(A)    The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  always  to 

be  confirmed  by  microscopical  examination  of  the  blood. 
Repeated  examinations  may  be  necessary. 

2.  Isolation — Exclusion   of  patient   from   approach   of   mos- 

quitoes, until  his  blood  is  rendered  free  from  malarial 
parasites  by  thorough  treatment  Avith  quinine. 

3.  Immunization — None.     The  administration  of  prophylac- 

tic doses  of  cjuinine  should  be  insisted  upon  for  those 
constantly  exposed  to  infection  and  unable  to  protect 
themselves   against   Anopheles   mosquitoes. 


358  HYGIENE  :     DENTAL    AND    GENERAL 

4.  Quarantine — None. 

5.  Concurrent      disinfection — None.     Destruction     of     Ano- 

pheles mosquitoes  in  the  sick  room. 

6.  Terminal  disinfection — None.     Destruction   of  Anopheles 

mosquitoes  in  sick  room. 
(B)    General  Measures — 

1.  Employment  of  known  measures  for  destroying  larvae  of 

anophelines  and  the  eradication  of  breeding  places  of 
such  mosquitoes. 

2.  Blood  examination  of  persons  living  in  infected  centers 

to  determine  the  incidence  of  infection. 

3.  Screening  sleeping  and  living  quarters;   use  of  mosquito 

nets. 
•4.  Killing  mosquitoes  in  living  quarters. 

Measles 

1.  Infectious  agent. — A  filterable  virus. 

2.  Source  of  infection. — Buccal  and  nasal  secretions  of  an  infected  in- 

dividual. 

3.  Mode   of  transmission. — ^Directly   from   person   to   person;    indirectly 

through  articles  freshly  soiled  with  the  buccal  and  nasal  discharges 
of  an  infected  individual.  The  most  easily  transmitted  of  all  com- 
municable diseases. 

4.  Incuhation  period. — Seven  to  eighteen  days ;  usually  14  days. 

5.  Period  of  communicahiUty. — ^During  the  j^eriod  of  catarrhal  symptoms 

and  until  the  cessation  of  abnormal  mucous  membrane  secretions — 
minimum  period  of  seven  days  from  two  days  before  to  five  days 
after  the  apjaearance  of  the  rash. 

6.  Methods  of  control: 

(A)   The  infected  individual  and  his  environment — 

1.  Eecognition   of  the   disease — Clinical  symptoms.     Special 

attention  to  rise  of  temperature,  Koplik  spots  and  ca- 
tarrhal symx^toms  in  exposed  individuals. 

2.  Isolation — During  period  of  communicability. 

3.  Immunization — None. 

4.  Quarantine — Exclusion     of     exposed     susceptible     school 

cliildren  and  teachers  from  school  until  14  days  from 
last  exposure.  Tliis  applies  to  exposure  in  the  house- 
hold. Exclusion  of  exposed  susceptible  children  from 
all  public  gatherings  for  the  same  period. 

.^.  Coucuvreuli  disinfection — All  articles  soiled  with  the  se- 
oi'tions  of  tlie  nose  and  throat. 

().   'J\'j-n]iiuil   disinfection — Tlun'ougli   ch'aiiiiig. 


THE    CONTROL    OF    COMMUNICABLE    DISEASES  359 

(B)   General  measures — 

1.  Daily  examination  of  exposed  children  and  of  other  pos- 

sibly exposed  persons.  This  examination  should  include 
record  of  the  body  temperature.  A  nonimmune  exposed 
individual  exhibiting  a  rise  of  temperature  of  0.5 °C.  or 
more  should  be  promptly  isolated  pending  diagnosis. 

2.  Schools  should  not  l)e  closed  or  classes  discontinued  where 

daily  observation  of  the  children  by  a  physician  or 
nurse  is  provided  for. 

3.  Education  as  to  special  danger  of  exposing  young  children 

to  tliose  exliibiting  acute  catarrhal  symptoms  of  any 
kind. 

Mumps 

1.  Infective  organism. — Unknown. 

2.  Source  of  infection. — Secretions   of   the   mouth   and   possibly   of   the 

nose. 

3.  Mode  of  traiLsmission. — By  direct  contact  with  an  infected  person  or 

with  articles  freshly   soiled  Avith   the   discharges   from  the   nose   or 

throat  of  such  infected  person. 

4..  Inouhation  period. — From  4  to  25  days.     The  most  common  period, 

18  days,  accepted  as  usual.     A  period  of  21  days  is  not  uncommon. 

5    Period,  of  communioability. — Unknown,  but  assumed  to  persist  until 

the  parotid  gland  has  returned  to  its  normal  size. 
(5.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Injflammation  of  Stcuo 's  duct 

may  be  of  assistance  in  recognizing  the  early  stage  of 
the  disease.  The  diagnosis  is  usually  made  on  swelling 
of  the  parotid  gland. 

2.  Isolation — Separation    of    tlie    patient    from    nonimmune 

children  and  exclusion  of  the  patient  from  school  and 
public  places  for  the  period  of  presumed  infectivity. 
(See  5). 

3.  Immunization — None. 

4.  Quarantine — Limited  to  exclusion  of  nonimmune  children 

from  school  and  public  gatherings  for  21  days  after 
last  exposure  to  a  recognized  case. 

5.  Concurrent  disinfection — All  articles  soiled  with  the  dis- 

charges from  the  nose  and  tliroat  of  tlve  patient. 
().  Terminal  disinfection — Xoiie. 

(B)  General  measures — 

None, 


360  HYGIENE:     DENTAL   AND   GENERAL 

Paratyphoid  Fever 

1.  Infectious  agent:  Bacillus  paratyphosus  A  or  B. 

2.  Source  of  infection:  Bowel  discharges  and  uiine  of  infected  persons, 

and  foods  contaminated  with  such  discharges  of  infected  persons 
or  of  healthy  carriers.  Healthy  carriers  may  be  numerous  in  an 
outbreak. 

3.  Mode   of  transmission:   Directly  by  personal  contact;    indirectly  by 

contact  with  articles  freshly  soiled  with  the  discharges  of  infected 
persons  or  through  milk,  water,  or  food  contaminated  by  such  dis- 
charges. 

4.  Incubation  period:  Four  to  ten  days;  average,  seven  days. 

5.  Period  of  communioadility :  From  the  appearance  of  prodromal  symp- 

toms, throughout  the  illness  and  relapses,  during  convalescence,  and 
until  repeated  bacteriological  examination  of  discharges  show  ab- 
sence of  the  infecting  organism. 

6.  Methods  of  Control: 

(A)  The  infected  individual  and  his  environment — - 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

by  specific  agglutination  test,  and  by  bacteriological  ex- 
amination of  blood,  bowel  discharges  or  urine. 

2.  Isolation — In   fly-proof   room,   preferably   under   hospital 

conditions,  of  such  cases  as  can  not  command  adequate 
sanitary  environment  and  nursing  care  in  their  homes. 

3.  Immunization  of  exposed  susceptibles. 

4.  Quarantine — None. 

5.  Concurrent    disinfection — Disinfection    of    all   bowel    and 

urinary  discharges  and  articles  soiled  with  them. 

6.  Terminal   disinfection — Cleaning. 

(B)  General  measures — 

1.  Purification  of  public  water  supplies. 

2.  Pasteurization  of  public  milk  supplies. 

3.  Supervision  of  other  food  supplies  and  of  food  handlers.* 

4.  Prevention  of  fly  breeding. 

5.  Sanitary  disposal  of  human  excreta. 

6.  Extension  of  immunization  by  vaccination  as  far  as  prac- 

ticable. 

7.  Supervision   of  paratyphoid  carriers   and   their   exclusion 

from  the  handling  of  foods. 

8.  Systematic   examination   of   fecal   specimens,   from   those 

who  have  been  in  contact  with  recognized  cases,  to  detect 
carriers. 


*The  human  disease  paratyphoid  fever  should  not  be  confused  with  cases  of  food 
poisoning,  or  infection  due  to  enteritidis  bacillj  of  animal  origin. 


THE    CONTROL    OF    COMMUNICABLE   DISEASES  361 

9.  Exclusion  of  suspected  milk  supplies  pending  discovery  of 
the  person  or  other  cause  of  contamination  of  the  milk. 
10.  Exclusion  of  water  supply,  if  contaminated,  until  ade- 
quately treated  with  hypochlorite  or  other  efficient  dis- 
infectant, or  unless  all  water  used  for  toilet,  cooking, 
and  drinking  purposes  is  boiled  before  use. 

Plague 

(Bubonic,  Septicemic,  Pneumonic) 

1.  Infectious  agent. — Bacillus  pestis. 

2.  Source   of   infection. — Blood   of   infected   persons   and   animals,    and 

sputum  of  human  cases  of  plague  pneumonia. 

3.  Mode   of    transmission. — Direct,    in   the   pneumonic    form.     In   other 

forms  the  disease  is  generally  transmitted  by  the  bites  of  fleas 
(Loemopsylla  cheopis  and  Ceratophyllus  fasciatus),  by  which  the 
disease  is  carried  from  rats  to  man,  also  by  fleas  from  other  rodents. 
Accidental,  by  inoculation,  or  by  the  bites  of  infected  animals. 
Bedbugs  may  transmit  the  infection;  flies  may  possibly  convey  the 
infection. 

4.  Incubation  period. — Commonly  from  3  to  7  days,  although  occasionally 

prolonged  to  8  or  even  li.  days. 

5.  Period  of  ooinmunicahility. — Until  convalescence  is  well  established, 

period  undetermined. 

6.  Methods  of  control: 

(A)   The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

by    bacteriological    examination    of    blood,    pus    from 
glandular  lesions,  or  sputum. 

2.  Isolation — Patient  in  hospital  if  practicable;   if  not,  in 

a  screened  room  wdiich  is  free  from  vermin.  •■' 

3.  Immnuization — Passive   immunization   of   known   exposed 

contacts;  active  immunization  of  those  who  may  be  ex- 
posed. 

4.  Quarantine — Contacts  for  seven  days. 

5.  Concurrent     disinfection — All     discharges     and     articles 

freshly  soiled  therewith. 

6.  Terminal    disinfection — Thorough    cleaning    followed    by 

thorough  disinfection. 


*In  plague  pneumonia,  personal  prophylaxis,  to  avoid  droplet  infection,  must  be 
carried  out  by  persons  who  come  in  contact  with  the  sick.  Masks  or  veils  of  cheese 
clotli  sliould  be  worn  as  protective  measures. 


362  -  HYGIENE:     DENTAL   AND    GENERAL 

(B)   General  measures — 

1.  Extermination    of    rats    and    vermin    by    use    of    known 

methods  for  their  destruction;  destruction  of  rats  on 
ships  arriving  from  infected  ports;  examination  of 
rats,  ground  squirrels,,  etc.,  in  areas  Avhere  the  infec- 
tion persists,  for  evidence  of  endemic  or  epidemic  prev- 
alence of  the  disease  among  them. 

2.  Supei-vision  of  autopsies  of  all  deaths  during  epidemics. 

3.  Supervision  of  the  disposal  of  the  dead  during  epidemics, 

whether  by  burial,  transfer,  or  holding  in  vault,  what- 
ever the  cause  of  death. 

4.  Cremation,  or  burial  in  quick  lime,  of  those  dying  of  this 

disease. 

Poliomyelitis 

1.  Infectious  agent:  Not  definitely  determined.     Believed  to  be  a  filter- 

able virus. 

2.  Source  of  infection:   Nose,  throat,  and  bowel  discharges  of  infected 

persons  or  articles  recently  soiled  therewith.  Healthy  carriers  are 
supposed  to  be  common. 

3.  Mode  of  transmission:  By  direct  contact  with  an  infected  person  or 

with  a  carrier  of  the  virus,  or  indirectly  by  contact  with  articles 
freshly  soiled  with  the  nose,  throat,  or  bowel  discharges  of  such 
persons. 

4.  Incubation  period:  From  3  to  10  days,  commonly  6  days. 

5.  Period  of  commuiiica'bility:  Unknown;   a^iparently  not  more  than  21 

days  from  the  onset  of  disease,  but  may  precede  onset  of  clinical 
symptoms  by  several  days. 

6.  Methods  of  control: 

(A)    The  infected  individual  and  his  environment — 

1.  Recognition   of   the   disease — Clinical   symptoms,   assisted 

by  chemical  and  microscopical  examination  of  the  spinal 
fluid. 

2.  Isolation  of  all  recognized  eases  in  screened  rooms. 

3.  Immunization — None. 

4.  Quarantine  of  exposed  children  of  the  household  and  of 

adults  of  the  household  Avhose  vocation  brings  them  into 
contact  with  children,  or  Avho  are  food  handlers,  for  14 
days  from  last  exposure  to  a  recognized  case. 

5.  Concurrent    disinfection — Nose,    throat,    and    bowel    dis- 

charges and  articles  soiled  therewith. 
(),   Terminal  disinfection — ('leaning. 


THE    CONTROL    OF    COMMUNICABLE    DISEASES  363 

(B)    General  measures  during  epidemics — 

1.  Search  for  and  examination  of  all  siek  children  should  be 

made. 

2.  All  children  with  fever  should  be  isolated  pending  diag- 

nosis. 

3.  Education  in   such   technique   of  bedside   nursing  as   will 

prevent  the  distrilnition  of  infectious  discharges  to 
others  from  cases  isolated  at  home. 

Rabies 

1.  Infections  agent:  Unknown. 

2.  Source  of  infection:  Saliva  of  infected  animals,  chiefly  dogs. 

3.  Mode   of   transmission:    Inoculation  with   saliva   of  infected  animals 

through  abrasion  of  skin  or  mucous  membrane,   almost   always  by 
bites  or  scratches. 
4.  liwiibation  perio'd:   Usually  2  to  6  weeks.     May  l)e  prolonged  to  6 
months  or  even  longer. 

5.  Period  of  com,municahilit\j :   For  l.j   days  in  the  dog   (not  known  in 

man)    before   the   onset   of   clinical   symptoms   and   throughout   tlie 
clinical  course  of  the  disease. 

6.  Methods  of  cantrol: 

(A)   The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

by  the  presence  of  Negri  bodies  in  the  brain  of  an  in- 
fected animal,  or  l)y  animal  inoculations  with  material 
from  the  brain  of  such  infected  animal. 

2.  Isolation — None  if  patient  is  under  adequate  medical  su- 

pervision, and  the  immediate  attendants  are  warned  of 
possibility  of  inoculation  by  human  virus. 

3.  Immunization — Preventive     vaccination     (Pasteur     treat- 

ment) after  exposure  to  infection  by  inoculation. 

4.  Quarantine — None. 

5.  Concurrent  disinfection   of  saliva  of  patieut  and  articles 

soiled  therewith, 
(i.  Terminal    disinfection — Thorough    cleaning.  ' 
(H)    General  measures — 

1.  ^Muzzling  of  dogs  when  on  public  streets,  or  in  jilnces  to 

Avliich  the  public  lias  access. 

2.  Detention  and  examination  of  dogs  suspected  of  having 

rabies. 

3.  Immediate  antirabic  treatment  of  people  bitten  by  dogs 

or  by  other  animals  suspected  or  known  to  have  rabies, 
unless  the  animal  is  proved  not  to  be  rabid  by  subse- 
(|uent  (>lisiM\  ation  or  liy  niicrosco[nc  exaniiiuitiou  of  the 
brain  and  cord. 


364  HYGIENE :     DENTAL   AND    GENERAL 

Pneumonia 

(Acute  Lobar) 

1.  Infectious  agent. — ^Various   pathogenic   bacteria   commonly   found   in 

the  nose,  throat,  and  mouth,  such  as  the  pneumoeoccus,  the  baccillus 
of  Friedlander,  the  influenza  bacillus,  etc. 

2.  Source  of  infection. — Discharges  from  the  mouth  and  nose  of  appar- 

ently healthy  carriers,  as  well  as  of  recognized  infected  individuals, 
and  articles  freshly  soiled  with  such  discharges. 

3.  Mode  of  transmission. — By  direct  contact  with  an  infected  person,  or 

with  articles  freshly  soiled  with  the  discharges  from  the  nose  or 
throat  of,  and  possibly  from  infected  dust  of  rooms  occupied  by, 
infected  persons. 

4.  Inculation  period. — Short,  usually  two  to  three  days. 

5.  Period  of  commmiicaMIity. — Unknown;   presumably  until  the  mouth 

and  nasal  discharges  no  longer  carry  the  infectious  agent  in  an 
abundant  amount  or  in  a  virulent  form. 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms.     Specific 

infecting  organisms  may  be  determined  by  serological 
and  bacteriological  tests  early  in  the  course  of  the  dis- 
ease. 

2.  Isolation — Patient   during  clinical  course  of  the  disease. 

3.  Immunization — None;    vaccines    are    worthy    of    further 

careful  trial. 

4.  Quarantine — None. 

5.  Concurrent    disinfection — Discharges   from   the   nose   and 

throat  of  the  patient. 

6.  Terminal    disinfection — Thorough    cleaning,    airing,    and 

sunning. 

(B)  General  measures — 

In  institutions  and  camps,  when  practicable,  people  in  large 
numbers  should  not  be  congregated  closely  within  doors. 
The  general  resistance  should  be  considered  by  good 
feeding,  fresh  air,  temperance  in  the  use  of  alcoholic 
beverages,  and  other  hygienic  measures. 

Note. — The  early  reporting  of  pneumonia  is  highly  desirable  in  view  of  its  coni- 
municability  and  the  possibility  of  effective  treatment  of  certain  types  with  cura- 
tive  sera. 

Rocky  Mountain  Spotted  or  Tick  Fever 

1.  Infectious  agent. — Unknown. 

2.  Source  of  infection. — Blood  of  infected  animals,   and  infected  ticks 

(Dcrmacentor  species). 


THE    CONTROL    OF    COMMUNICABLE    DISEASES  365 

3.  Mode  of  transmission. — By  bites  of  infected  ticks. 
A.  Incubation  period. — Three  to  ten  days,  usually  seven  days. 
5.  Period  of  communicahility. — Has  not  been  definitely  determined,  prob- 
ably during  the  febrile  stage  of  the  disease. 
<\  Methods  of  control : 

(A)  Tlie  infected  individual  and  liis  environment — 

1.  Recognition  of  the  disease — By  clinical  symptoms  of  the 

disease  in  areas  -where  the  disease  is  known  to  be  en- 
demic. 

2.  Isolation — None,  other  than  care  exercised  to  protect  pa- 

tients from  tick  bites  Avhen  in  endemic  areas. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — None.     All  ticks  on  the  patient 

should  be  destroyed. 

6.  Terminal  disinfection — None. 

(B)  General  measures — 

1.  Personal   prophylaxis    of    persons    entering   the    infected 

zones  during  the  season  of  ticks,  by  wearing  tick-proof 
clothing,  and  careful  daily  search  of  the  body  for  ticks 
which  may  have  attached  themselves. 

2.  The  destruction  of  ticks  by  clearing  and  burning  vegeta- 

tion on  the  land  in  infected  zones. 

3.  The  destruction  of  ticks  on  domestic  animals  by  dipping, 

and  the  pasturing  of  sheep  on  tick  infested  areas  where 
the  disease  is  prevalent,  with  the  object  of  diminishing 
the  number  of  ticks. 

4.  The    destruction    of    small    mammalian    hosts    as    ground 

squirrels,  chipmunks,  etc. 

Scarlet  Fever 

1.  Infectious  agent. — Unknown. 

2.  Source  of  infection. — The  belief  at  present  is  that  the  virus  is  con- 

tained in  the  secretions  from  the  nose  and  throat,  in  the  blood  and 
in  the  lymph  nodes,  and  that  it  is  given  off  in  the  discharges  from 
the  mouth,  the  nose,  the  ears,  and  from  brokendown  glands  of  in- 
fected persons. 

3.  Mode  of  transmission. — Directly  by  personal  contact  with  an  infected 

person;  indirectly  by  articles  freshly  soiled  with  discharges  of  an 
infected  person,  or  through  contaminated  milk. 

4.  Incubation  period. — Two  to  seven  days,  usually  three  or  four  days. 

5.  Period  of  eommunicabiUty. — Four  weeks  from  the  onset  of  the  disease, 

without  regard  to  desquamation,  and  until  all  abnormal  discharges 
have  stopped  and  all  open  sores  have  healed. 


366  HYGIENE :     DENTAL   AND    GENERAL 

G.  Metliods  of  control. — 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — By  clinical  symptoms. 

2.  Isolation — In  home  or  hospital,  maintained  in  each  case 

\intil  the  end  of  the  period   of  infectivity. 

3.  Immunization — None. 

4.  Quarantine — Exclusion    of    exposed    susceptiljle    children 

and  teachers  from  school,  and  food  handlers  from  their 
work,  until  seven  days  have  elapsed  since  last  exposure 
to  a  recognized  ease. 

5.  Concurrent  disinfection — Of  all  articles  which  have  been 

in  contact  with  a  patient  and  all  articles  soiled  with 
discharges  of  the  patient. 

6.  Terminal  disinfection — Thorough  cleaning. 

(B)  General  measures — 

1.  Daily  examination  of  exposed  children  and  of  other  pos- 

sibly exposed  persons  for  a  week  after  last  exposure. 

2.  Schools  should  not  be  closed  where  daily  observation  of 

the  children  by  a  physician  or  nurse  can  be  provided  for. 

3.  Education  as  to  special  danger  of  exposing  young  children 

to  those  exhibiting  acute  catarrhal  symptoms  of  any 
kind. 

4.  Pasteurization  of  milk  supply. 

Septic  Sore  Throat 

1.  Infectious  agent. — Streptococcus   (hemolytic  type). 

2.  Source  of  infection. — The  human  naso-pharynx,   usually   the  tonsils, 

any  case  of  acute  streptococcus  inflammation  of  these  structures  be- 
ing a  potential  source  of  infection,  including  the  period  of  convales- 
cence of  such  cases.  The  udder  of  a  cow  infected  by  the  milker  is 
an  occasional  source  of  infection.  In  such  udders  the  i^hysical  signs 
of  mastitis  are  usually  absent.* 

3.  Mode  of  transmission. — Direct  or  indirect  human  contact;   consump- 

tion of  raw  milk  from  an  infected  udder. 

4.  iTKnibation  period. — One  to  three  days. 

5.  Period  of  communicahility . — In  man,  presumably  during  the  continu- 

ance of  clinical  symptoms;  in  the  cow,  during  the  continuance  of 
discharge  of  the  streptococci  in  the  milk,  the  condition  in  the  udder 
tending  to  a  spontaneous  subsidence.  The  carrier  stage  may  follow 
convalescence  and  i^ersist  for  some  time. 


■"Mastitis  in  tlie  cow,  due  to  bovine  streptococci,  is  not  a  cause  of  septic  sore 
throat  in  humans  unless  a  secondary  infection  of  the  udder  Ijy  a  human  type  of 
streptococcus  takes  place. 


THE    rOXTROI.    OF    COMMTXICAHLE    DISEASES  367 

6.  Methods  of  contiol: 

(A)  The  infected  individual  and  liis  environment — 

1.  Eeeognition  of  the  disease — Clinical  symptoms.  Bac- 
teriological examination  of  the  lesions  or  discharges  from 
the  tonsils  and  naso-pharynx  may  be  useful. 
2.  Isolation — During  the  clinical  course  of  the  disease  and 
convalescence,  and  particularly  exclusion  of  the  patient 
from  pai'ticipation  in  the  jiroduction  or  handling  of  milk 
or  milk  products. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent   disinfection — Articles   soiled   with   discharges 

from  the  nose  and  throat  of  the  patient. 

6.  Terminal  disinfection — Cleaning. 

(B)  General  measures — 

1.  Exclusion  of  suspected  milk  supply  from  public  sale  or 

use,  until  pasteurized.  The  exclusion  of  the  milk  of 
an  infected  cow  or  cows  in  small  herds  is  possible  when 
based  on  bacteriological  examination  of  the  milk  of 
each  cow,  and  preferably  the  milk  from  each  c^uarter  of 
the  udder  at  frequent  inteiTals. 

2.  Pasteurization  of  all  milk. 

3.  Education  in  the  i^rinciples  of  personal  hygiene  and  avoid- 

ance of  the  use  of  common  towel,  drinking  and  eating 
utensils. 

Smallpox 

1.  Infectious  agent. — Unknown. 

2.  Source  of  infection. — Lesions  of  the  skin  and  mucous  membranes  of 

infected  persons. 

3.  Mode  of  transmission. — By  direct  personal  contact;  by  articles  soiled 

with  discharges  from  lesions.     The  virus  may  be  present  in  all  body 
discharges,  including  feces  and  urine.     It  may  be  carried  by  flies. 

4.  Incubation  period. — Twelve  to  fourteen  days.     (Cases  Avith  incubation 

period  of  21  days  are  reported.) 

5.  Penod  of  comrmmieahiUt y . — From   first   symptoms  to   disappearance 

of  all  scabs  and  crusts. 
6    Methods  of  control: 

(A)   The  infected  individual  and  his  environment — 

1.  Eeeognition  of  the  disease^ — Clinical  symptoms.     Tests  for 

immunity  may  prove  useful. 

2.  Isolation — Hospital  isolation  in  screened  wards,  free  from 

vermin,  until  the  period  of  infectivity  is  over. 


368  HYGIENE  :     DENTAL    AND    GENERAL 

3.  Immunization — Vaccination. 

4.  Quarantine — Segregation   of   all   exposed   persons   for   21 

days  from  date  of  last  exposure,  or  until  protected  by 
vaccination. 

5.  Concurrent    disinfection    of    all    discharges    and    articles 

soiled  therewith. 

6.  Terminal   disinfection — Thorough   cleaning   and   disinfec- 

tion of  premises. 
(B)   General  measures — 

General  vaccination  in  infancy,  revaccination  of  children  on 
entering  school,  and  of  entire  population  when  the  dis- 
ease is  prevalent. 

Note. — Adjustment  of  the  time  of  vaccination  of  infants  to  avoid  teething  or 
other  mild  and  common  indispositions,  the  time  of  vaccination  of  children  of  the 
runabout  age  and  older  with  preference  for  the  cool  months  of  the  year,  and  the 
manner  of  vaccination  with  preference  for  the  single  puncture  or  small  area  scratch 
method  through  the  droplet  of  virus  are  important  to  observe  in  order  to  avoid 
possible  complications  or  secondary  and  subsequent  infections  at  the  site  of  vac- 
cination.    Vaccination  before  the  age   of  six  months  is  particularly  desirable. 

Syphilis 

1.  Infectious  agent. — Treponema  pallidum. 

2.  Source  of  infection. — Discharges   from   the   lesions   of   the   skin   and 

mucous  membranes,  and  the  blood  of  infected  persons,  and  articles 
freshly  soiled  with  such  discharges  or  blood  in  which  the  Treponema 
pallidum  is  present. 

3.  Mode    of    t7'ansnnission. — By    direct    personal    contact    with    infected 

persons,  and  indirectly  by  contact  with  discharges  from  lesions  or 
with  the  blood  of  such  persons. 

4.  Inctiiation  period. — ^About  three  weeks.     (In  rare  instances  reported 

to  have  been  as  long  as  70  days.) 

5.  Period  of  communicability. — As  long  as  the  lesions  are  open  upon  the 

skin  or  mucous  membranes  and  until  the  body  is  freed  from  the 
infecting  organisms,  as  shown  by  microscopic  examination  of  mate- 
rial from  ulcers  and  by  serum  reactions. 

6.  Methods  of  control: 

(A)   The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

by  microscopical  examination  of  discharges,  and  by 
serum  reactions. 

2.  Isolation — Exclusion     from     sexual     contact     and     from 

preparation  or  serving  of  food  during  the  early  and 
active  period  of  the  disease ;  otherwise  none,  unless  the 
patient  is  unwilling  to  heed,  or  is  incapable  of  observing, 
the  precautions  required  by  the  medical  adviser. 


THE    CONTROL    OF    COMMUNICABLE    DISEASES  369 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent    disinfection    of    discharges    and    of    articles 

soiled  therewith. 

6.  Terminal  disinfection — None. 
(B)   General  measures — 

1.  Education  in  matters  of  sexual  hygiene,  particularly  as 

to  the  fact  that  continence  in  both  sexes  and  at  all 
ages  is  compatible  with  health  and  development. 

2.  Provision  for  accurate  and  early  diagnosis  and  treatment, 

in  hospitals  and  dispensaries,  of  infected  persons,  with 
consideration  for  privacy  of  record,  and  provision  for 
following  cases  until  cured. 

3.  Eepression  of  prostitution  by  use  of  the  police  power  and 

control  of  use  of  living  premises. 

4.  Eestriction  of  sale  of  alcoholic  beverages. 

5.  Eestriction   of   advertising   of   services   or   medicines   for 

treatment  of  sex  diseases,  etc. 

6.  Abandonment   of   the   use   of   common   towels,   cups,   and 

toilet  articles  and  eating  utensils. 

7.  Exclusion  of  persons  in  the  communicable  stage   of  the 

disease  from  participation  iu  the  preparing  and  serv- 
ing of  food. 

8.  Personal  prophylaxis  should  be  advised  to  those  who  ex- 

pose themselves  to  opportunity  to  infection. 

Tetanus 

1.  Infectious  agent:  Bacillus  tetani. 

2.  Soxirce  of  infection:   Animal  manure,  and  soil  fertilized  with  animal 

manure,  and,  rarely,  the  discharges  from  wounds. 

3.  Mode  of  transmission:  Inoculation,  or  wound  infection. 

4.  Inciihation  period:   Six  to  fourteen  days,  usually  nine. 

0.  Period  of  oomimunicability :  Patient  not  infectious  except  in  rare  in- 
stances where  wound  discharges  are  infectious. 

6.  Methods  of  control: 

(A)   The  infected  individual  and  his  environment — 

1.  Eecognition   of  the   disease — Clinical   sympitoms;   may  be 

confirmed  bacteriologieally. 

2.  Isolation — None. 

3.  Immunization — By  antitoxin,  single  or  repeated  injection. 

4.  Quarantine — None. 

5.  Concurrent  disinfection — None. 

6.  Terminal   disinfection — None. 


370  HYGIENE:     DEXTAL   AND    GENERAL 

(B)   General  measures — 

1.  SuperTision  of  the  practice  of  obstetrics. 

2.  Ediicatioual    propagauda    such    as    "safety-first"    cam- 

paign, and  "safe  and  sane  Fourth  of  July"  campaign. 

3.  Prophylactic  use  of  tetanus  antitoxin  where  wounds  have 

been  acquired  in  regions  where  the  soil  is  known  to  be 
heavily  contaminated,  and  in  all  cases  where  wounds 
are  ragged  or  penetrating. 

4.  Eemoval  of  all  foreign  matter  as  early  as  possible  from 

all  wounds. 

5.  Supervision    of    biological    products,    especially    vaccines 

and  sera. 

Trachoma 

1.  Infectious  agent -.^  The  chief,  although  not  yet  known  to  be  the  only, 

infectious  agents  are  the  hemoglobin ophilic  bacilli  including  the  so- 
called  Koch-Weeks  bacillus. 

2.  Source  of  infection:  Secretions  and  purulent  discharges  from  the  con- 

junctivae and  adnexed  mucous  membranes  of  the  infected  persons. 

3.  Mode  of  transmssion:  By  direct  contact  with  infected  persons  and  in- 

directly by  contact  with  articles  freshly  soiled  with  the  infective  dis- 
charges of  such  persons. 

4.  Incubation  period:  Undetermined. 

5.  Period  of  commmnicaJ)ility :  During  the  persistence  of  lesions  of  the 

conjunctivae  and  of  the  adnexed  mucous  membranes  or  of  discharges 
from  such  lesions. 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition    of    the    disease — Clinical    symptoms.     Bac- 

teriological examination  of  the  conjunctival  secretions 
and  lesions  may  be  useful. 

2.  Isolation. — Exclusion  of  the  patient  from  general  school 

classes. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection  of  discharges  and  articles  soiled 

therewith. 

6.  Terminal  disinfection — None. 

(B)  General  measures — 

1.  Search'  for  cases  by  examination  of  school  children,  of 
immigrants,  and  among  the  families  and  associates  of 
recognized  cases;  in  addition,  search  for  acute  secret- 
ing disease   of   conjunetivge  and  adnexed  mucous  mem- 


*It  has  not  yet  been  proven   that  trachoma  is   due   to   one   specific   organism. 


THE    COXTROT.    OF    COM^rnXICABLE   DISEASES  371 

brancs,  both   among  school   children  and  in  their   fam- 
ilies, and  treatment  of  such  cases  until  cured. 

2.  Elimination   of   common   towels   and  toilet   articles   from 

public  places. 

3.  Education   in  the  principles   of  personal   cleanliness  and 

the   necessity    of   avoiding   direct   or   indirect   transfer- 
ence of  body  discharges. 

4.  Control   of  public   dispensaries   Avhere   communicable   eye 

diseases  are  treated. 

Trichinosis 

1.  Infectious  agent. — Trichinella  spiralis. 

2.  Source  of  infection. — Uncooked  or  insufficiently  cooked  meat   of  in- 

fected hogs. 

3.  Mode   of  transmission. — Consumption   of   undercooked   infected   pork 

products. 

4.  Incuhation  period. — Variable;  usually  about  one  week. 

5.  Period   of   comvmnicaliility. — Disease    is   not   transmitted   by   human 

host. 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms,  confirmed 

by  microscopical  examination  of  muscle  tissue  contain- 
ing trichina;. 

2.  Isolation — None. 

3.  Immunization — Xone. 

4.  Quarantine — Xone. 

5.  Concurrent   disinfection — Sanitary   disposal   of   the   feces 

of  the  patient. 

6.  Terminal  disinfection — Xone. 

(B)  General  measures — 

1.  Inspection  of  pork  products  for  the   detection  of  trichi- 

nosis. 

2.  Thorough  cooking  of  all  pork  products  at  a  temperature 

of  160  °F.  or  over. 

Tuberculosis  (Pulmonary) 

1.  Infectio-us     agent. — Bacillus     tuberculosis     (human).      (In     rare     in- 

stances  the   bovine    tubercle   bacillus   has   been   proved   to   be   the 
cause  of  a  pulmonary  tuberculosis.) 

2.  Source  of  infection. — The  specific  organism  present  in  the  discharges, 

or  articles  freshly  soiled  with  the  discharges  from  any  open  tubercu- 


372  HYGIENE  :     DENTAL   AND    GENERAL 

lous  lesions,  the  most  important  discharge  being  sputum.  Of  less 
importance  are  discharges  from  the  intestinal  and  genito-urinary 
tracts,  or  from  lesions  of  the  lymphatic  glands,  bone,  and  skin. 

3.  Mode  of  transmission. — ^Direct  or  indirect   contact  with  an  infected 

person  by  coughing,  sneezing,  or  other  droplet  infection,  kissing, 
common  use  of  unsterilized  food  utensils,  pipes,  toys,  drinking 
cups,  etc.,  and  possibly  by  contaminated  flies  and  dust. 

4.  Incubation  period. — Variable   and   dependent  upon  the   type   of  the 

disease. 

5.  Period  of  communicaMlity. — Exists  as  long  as  the  specific  organism 

is  eliminated  by  the  host.  Commences  when  a  lesion  becomes  an 
open  one,  i.  e.,  discharging  tubercle  bacilli,  and  continues  until 
it  heals  or  death  occurs. 

6.  Methods  of  control: 

(A  The  infected  individual  and  his  environment — 

1.  Recognition  of  the  disease — By  clinical  symptoms  and  by 

thorough  physical  examination,  confirmed  by  bacterio- 
logical examination  and  by  serological  tests. 

2.  Isolation  of  such  "open"   cases  as  do   not   observe  the 

precautions  necessary  to  prevent  the  spread  of  the  dis- 
ease. 

3.  Immunization — None. 

4.  Quarantine — None. 

5.  Concurrent  disinfection  of  sputum  and  articles  soiled  with 

it.  Particular  attention  should  be  paid  to  prompt  dis- 
posal or  disinfection  of  sputum  itself,  of  handkerchiefs, 
cloths,  or  paper  soiled  therewith,  and  of  eating  utensils 
used  by  the  patient. 

6.  Terminal  disinfection — Cleaning  and   renovation. 
(B)   General  measures — 

1.  Education    of    the    public   in   regard   to   the    dangers    of 

tuberculosis  and  the  methods  of  control,  -with  especial 
stress  upon  the  danger  of  exposure  and  infection  in  early 
childhood. 

2.  Provision   of   dispensaries   and  visiting-nurse   service   for 

discovery  of  early  cases  and  supervision  of  home  cases. 

3.  Provision  of  hospitals  for  isolation  of  advanced  cases,  and 

sanatoria  for  the  treatment  of  early  cases. 

4.  Provision   of   open-air   schools   and   preventoria   for   pre- 

tuberculous  children. 

5.  Improvement  of  housing  conditions,  and  the  nutrition  of 

the  poor. 

6.  Ventilation,  and  elimination  of  dusts  in  industrial  estab- 

lishments and  places  of  public  assembly. 


THE    CONTROL    OF    COMMUNICABLE   DISEASES  373 

7.  Improvement   of  habits  of  personal  hygiene   and  better- 

ment of  general  living  conditions. 

8.  Separation  of  babies  from  tuberculous  mothers  at  birth. 

Tuberculosis  (Other  than  Pulmonary) 

1.  Infectious  agent. — Bacillus  tuberculosis   (human  and  bovine). 

2.  Source  of  infection. — Discharges  from  mouth,  nose,  bowels  and  genito- 

urinary tract  of  infected  humans  j  articles  freshly  soiled  with  such 
discharges;  milk  from  tuberculous  cattle;  rarely  the  discharging 
lesion  of  bones,  joints,  and  lymph  nodes. 

3.  Mode  of  transmission. — By  direct  contact  with  infected  persons,  by 

contaminated  food,  and  possibly  by  contact  with  articles  freshly 
soiled  with  the  discharges  of  infected  persons. 

4.  Incubation  period. — Unknown. 

5.  Period  of  communicability . — Until  lesions  are  healed. 

6.  Metliods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognition  of  the  disease — Clinical  symptoms  confirmed 

by  bacteriological  and  serological  examinations. 

2.  Isolation. — None. 

3.  Immunization. — None. 

4.  Quarantine. — None. 

5.  Concurrent  disinfection. — Discharges  and  articles  freshly 

soiled  with  them. 

6.  Terminal  disinfection. — Cleaning. 

(B)  General  measures — 

1.  Pasteurization  of  milk  and  inspection  of  meats. 

2.  Eradication  of  tuberculous  cows  from  milch  herds  used 

in  supplying  raw  milk. 

3.  Patients   with    open    lesions    should    be    prohibited    from 

handling  foods  which  are  consumed  raw. 

Typhoid  Fever 

1.  Infectious  agent. — Bacillus  tyi^hosus. 

2.  Source  of  infection. — Bowel  discharges  and  urine  of  infected  individ- 

uals.    Healthy  carriers  are  common. 

3.  Mode  of  transmission. — Conveyance  of  the  specific  organism  by  direct 

or  indirect  contact  with  a  source  of  infection.  Among  indirect 
means  of  transmission  are  contaminated  water,  milk,  and  shellfish. 
Contaminated  flies  have  been  common  means  of  transmission  in 
epidemics. 

4.  Incubation  period. — From  7  to  23  days,  averaging  10  to  14  days. 


374  HYGIENE:     DENTAL   AND   GENERAL 

5.  Period    of    commuivicability. — From    the    appearance    of    prodromal 

symptoms,  throughout  the  illness  and  relapses  during  convalescence, 
and  until  re]peated  bacteriological  examinations  of  the  discharges 
show  persistent  absence  of  the  infecting  organism. 

6.  MeiJwds  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Recognition  of  the  disease — -Clinical  symptoms,  confirmed 

by  specific  agglutination  test  and  bacteriological  exami- 
nation of  blood,  boAvel  discharges,  or  urine. 

2.  Isolation — In   fly-proof   room,   preferably   under   hospital 

conditions,  of  such  cases  as  can  not  command  adequate 
sanitary  environment  and  nursing  care  in  their  homes. 

3.  Immunization — Of   susceptibles   who   are   known   to   have 

been  exposed  or  are  suspected  of  having  been  exposed. 

4.  Quarantine — None. 

5.  Concurrent    disinfection — Disinfection    of    all   boAvel    and 

urinary  discharges  and  articles  soiled  with  them. 

6.  Terminal  disinfection — Cleaning. 

(B)  General  measures — - 

1.  Purification  of  public  water  supplies. 

2.  Pasteurization  of  public  milk  supplies. 

3.  Supervision  of  other  food  supplies,  and  of  food  handlers. 

4.  Prevention   of  fly  breeding. 

5.  Sanitary  disj^osal  of  human  excreta. 

6.  Extension  of  immunization  by  vaccination  as  far  as  prac- 

ticable. 

7.  Supervision  of  typhoid  carriers  and  their  exclusion  from 

the  handling  of  foods. 

8.  Systematic   examination    of   fecal   specimens   from   those 

who  have  been  in  contact  with  recognized  cases,  to  de- 
tect carriers. 

9.  Exclusion  of   suspected   milk   supplies   pending   discovery 

of  the  person  or  other  cause  of  contamination  of  the 
milk. 
10.  Exclusion  of  water  supply,  if  contaminated,  until  ade- 
quately treated  with  hyjiochlorite  or  other  efficient  dis- 
infectant, or  unless  all  Avater  used  for  toilet,  cooking, 
and  drinking  purposes  is  boiled  before  use. 

Typhus  Fever 

1.  Infectious  agent:   Bacillus  typhi-exanthematici  is   claimed  to  be  the 

causative  agent;  not  yet  definitely  determined. 

2.  Source  of  infection:  The  blood  of  infected  individuals. 


THE    CONTROL    OF    COMMUNICABLE   DISEASES  375 

3.  Mode  of  transmission:   Infectious  agent  transmitted  by  lice.      (Pedic- 

ulus  corporis,  P.  capitis.) 

4.  Incuiation  pen-iod:   Five  to  twenty  days,  usually  twelve  days. 

5.  Period  of  aommunic-ability :   Until  36  hours  have  elapsed  after  the 

temperature  reaches  normal. 

6.  Methods  of  control: 

(A)  The  infected  individual  and  his  environment — 

1.  Eecognitiou    of    the    disease — Clinical    symptoms.      (Con- 

firmation by  bacteriological  examination  of  blood 
claimed  by  Plotz.) 

2.  Isolation — In  a  vermin-free  room.     All  attendants  should 

wear  vennin-proof  clothing. 

3.  Immunization — Claimed  to  be  practicable  by  use  of  vac- 

cine (Plotz,  Olitzky,  and  Baehr).  Not  yet  generally 
accepted. 

4.  Quarantine- — Exposed  susceptibles  for  12  days  after  last 

exposure. 

5.  Concurrent   disinfection — None. 

6.  Terminal    disinfection — Destroy    all    vermin   and    vermin 

eggs  on.  body  of  patient,  if  not  already  accomplished. 
Destroy  all  vermin  and  eggs  on  clothing.  Eooms  to  be 
rendered  free  from  vermin. 

(B)  General  measures — 

Delousing  of  persons,  clothing,  and  premises  during  epi- 
demics, or  when  they  have  come  or  have  been  brought 
into  an  uninfected  place  from  an  infected  community. 

Whooping-  Cough 

1.  Infectious  agent:   Bacillus  pertussis   (Bordet,   Geugou). 

2.  Source   of  infection:    Discharges   from   the   laryngeal   and   bronchia] 

mucous  membranes  of  infected  persons  (sometimes  also  of  infected 
dogs  and  cats,  which  are  known  to  be  susceptible). 

3.  Mode  of  transmission :  Contact  with  an  infected  person  or  animal  or 

with  articles  freshly  soiled  with  the  discharges  of  such  person  or 
animal. 

4.  Inouhation  period:    Within  14  days. 

5.  Period  of  communicahility :   Particularly  cominunicublc  in  the   early 

catarrhal  stages  before  the  characteristic  whoop  makes  the  clinical 
diagnosis  possible.  Communicability  probably  jiersists  not  longer 
than  two  weeks  after  the  development  of  the  characteristic  whoop 
or  approximately  four  weeks  after  the  onset  of  catarrhal  symptoms. 

6.  Methods  of  control: 

(A)   The  infected  individual  and  his  environment — 


376  HYGIENE :     DENTAL   AND    GENERAL 

1.  Eecognition  of  the  disease — Clinical  symptoms,  supported 

by  a  differential  leucocyte  count,  and  confirmed  where 
possible  by  bacteriological  examination  of  bronchial  se- 
cretions. 

2.  Isolation — Separation    of    the    patient    from    susceptible 

children,  and  exclusion  of  the  patient  from  school  and 
public  places,  for  the  period  of  presumed  infectivity. 

3.  Immunization — Use    of    prophylactic    vaccination    recom- 

mended by  some  observers.     Not  effective  in  all  cases. 

4.  Quarantine — Limited  to  the  exclusion  of  nomimmune  chil- 

dren from  school  and  public  gatherings  for  14  days 
after  their  last  exposure  to  a  recognized  case. 

5.  Concurrent   disinfection — Discharges   from   the   nose   and 

throat  of  the  patient  and  articles  soiled  with  such  dis- 
charges. 

6.  Terminal  disinfection — Cleaning  of  the  premises  used  by 

the  patient. 
(B)   General  measures — 

Education  in  habits  of  personal  cleanliness  and  in  the  dan- 
gers of  association  or  contact  with  those  showing  ea- 
tairrhal  symptoms  with  cough. 

Yellow  Fever 

1.  Infectious  agent. — Unknown. 

2.  Source  of  infection. — The  blood  of  infected  persons. 

3.  Mode  of  transmission. — By  the  bite  of  infected  Aedes  calopus  mos- 

quitoes. 

4.  Inciihation  period. — Three  to  five  days,  occasionally  six  days. 

5.  Period  of  commumcahility.— First  three  days  of  the  fever. 

6.  Metliods  of  control: 

(A)   The  infected  individual  and  his  environment — - 

1.  Recognition  of  the  disease — Clinical  symptoms. 

2.  Isolation — Isolate  from  mosquitoes  in  a  special  hospital 

Avard  or  thoroughly  screened  room.  If  necessary  the 
room  or  ward  should  be  freed  from  mosquitoes  by  fumi- 
gation. Isolation  necessary  only  for  the  first  three 
days  of  the  fever. 

3.  Immunization — None. 

4.  Quarantine — Contacts  for  six  days. 

5.  Concurrent  disinfection — None. 

6.  Terminal  disinfection — None.     Upon  termination  of  case 

the  premises  should  be  rendered  free  from  mosquitoes  by 
fumigation. 


THE    CONTROL    OF    COMMUNICABLE   DISEASES  377 

(B)  General  measures — 

Eliminate  mosquitoes  by  rendering  breeding  impossible. 

(C)  Epidemic  measures — 

1.  Inspection  service  for  the  detection  of  those  ill  with  the 

disease. 

2.  Fumigation    of    houses   in   which   eases    of    disease    have 

occurred,  and  of  all  adjacent  houses. 

3.  Destruction  of  Aedes  calopus  mosquitoes  by  fumigation; 

use  of  larvicides;   eradication  of  breeding  places. 


APPENDIX  B 

DISINFECTION  AND  DISINFECTANTS 

The  purpose  of  adding  this  appendix  is  to  give  a  brief  state- 
ment of  the  chemical  and  physiological  principles  involved  in 
the  action  of  the  various  disinfectants  and  certain  facts  rel- 
ative to  their  use,  which  may  be  convenient  for  the  reference 
of  the  dental  practitioner. 

Definitions. — A  few  definitions  will  be  necessary  as  a  basis 
for  discussion. 

Disinfection  means  the  destruction  of  the  agents  causing 
infection. 

Sterilization  refers  to  the  destruction  of  all  forms  of  life 
in  a  certain  medium  or  location. 

Sepsis  is  a  bacteriological  process  of  decay. 

Antiseptics  are  substances  which  prevent  decomposition 
and  decay.     They  do  not  necessarily  destroy  the  organisms. 

Asepsis  is  the  absence  of  living  organisms. 

A  germicide  is  a  substance  which  has  the  power  of  destroy- 
ing germs. 

A  deodorant  is  a  substance  which  destroys  or  neutralizes  the 
odors  arising  from  the  putrefaction  or  fermentation  of  organic 
substances. 

Disinfection  Versus  Sterilization. — Most  organisms  which 
produce  disease  are  not  spore-forming  and  it  is,  therefore, 
possible  to  disinfect  in  most  instances  without  complete  steri- 
lization. "Material  containing  the  bacilli  of  tetanus  and  an- 
thrax or  the  bacillus  of  malignant  edema  or  B.  welchii  re- 
quires sterilization  because  these  bacilli  form  spores. 

Dry  heat  at  a  temperature  of  160°  C.  or  a  temperature  of 
150°  C.  maintained  for  one  hour  will  kill  spores.  Steam 
under  a  pressure  of  15  pounds  per  square  inch  will  kill  spores 

378 


DISINFECTION    AND    DISINFECTANTS  379 

in  fifteen  minutes.  Steam  at  15  lbs.  pressure  has  a  tempera- 
ture of  about  120°  C. 

Antiseptics.— Sugar  and  salt  are  the  ordinary  household 
antiseptics.  These  substances  like  freezing  or  drying  prevent 
the  development  of  the  microorganisms  Mdiich  may  still  remain 
alive.  "Weak  solutions  of  certain  disinfectants  like  mercury 
bichloride  are  antiseptic  substances. 

Deodorants. — Dryness  is  the  great  natural  deodorant.  Sub- 
stances which  are  thoroughly  dried  will  not  give  off  disagree- 
able smells.  An  example  of  this  is  seen  in  the  sanitary  dr}- 
privy.  Dryness  sufficient  to  deodorize,  however,  is  not  suf- 
ficent  to  sterilize  or  disinfect. 

Of  the  chemical  substances  formaldehyde  is  an  excellent 
deodorant  as  well  as  germicide  since  it  combines  directly  with 
the  putrefactive  substances  to  form  new  substances  which  are 
not  malodorants. 

Fumigation. — Fumigation  is  a  process  of  liberating  gases 
or  fumes  for  the  purpose  of  destroying  the  causes  of  infection 
or  possible  carriers  of  infection.  Fumigation  may  therefore 
be  directed  either  against  germs  or  against  insects  and  other 
animals  which  spread  disease.  It  is  now  chiefly  used  to  kill 
insects  and  other  animals.  There  is  a  wide  difference  be- 
tween fumigation  and  disinfection  and  the  two  words  should 
not  be  used  interchangeably.  The  ordinary  f umigants  are  for- 
maldehyde gas,  sulphur  dioxide  (SOJ,  hydrocyanic  acid 
(HON),  the  halogens,  carbon  bisulphide  (CSo),  carbon 
tetrachloride  (CCl^),  and  pyrethrum. 

Disinfection. — It  is  important  to  know  Avliat  to  disinfect, 
how  to  disinfect,  and  when  to  disinfect  in  order  that  the  work 
may  be  done  efficiently  and  completely.  Bedside  and  contin- 
uous disinfection  is  far  more  important  than  terminal  fumiga- 
tion in  preventing  the  spread  of  disease.  In  controlling  any 
communicable  disease  the  causative  organism  and  modes  of 
transmission  should  be  thoroughly  understood. 

Control  of  Disinfection. — The  efficiency  of  a  disinfecting 
process  may  be  determined  l)y  saturating  cotton  threads  with 


380  HYGIENE:     DENTAL   AND   GENERAL 

a  culture  of  B.  prodigiosus,  grown  in  Dunham's  Peptone 
Medium.  These  threads  are  subjected  to  the  process  of  dis- 
infection with  the  other  material,  then  planted  in  tubes  of 
sterile  broth  where  growth  may  be  readily  determined  by  the 
development  of  red  color. 

Natiiral  Disinfection. — Nature's  disinfecting  agencies  in- 
clude (1)  dilution,  as  exemplified  by  the  purification  of  pol- 
luted water  by  storage,  (2)  sunlight,  which  kills  organisms  by 
its  actinic  rays;  (3)  dryness  if  sufficient  and  prolonged  and 
(4)  symbiosis,  as  exemplified  in  the  destruction  of  disease 
germs  in  sewage  by  the  action  of  the  bacteria  of  putrefaction. 

The  Ideal  Disinfectant  has  not  yet  been  found.  Such  a 
substance  would  be  highly  germicidal,  free  from  organic  mat- 
ter, reasonably  stable,  soluble  or  readily  miscible  in  water 
forming  a  permanent  emulsion ;  it  should  be  harmless  to  man 
and  the  higher  animals,  possessed  of  a  good  power  of  penetra- 
tion without  bleaching  fabrics  or  pigments  and  corroding 
metals. 

Standardizing  Disinfectants. — In  order  that  we  may  have 
a  terminology  by  which  the  disinfecting  power  of  a  substance 
may  be  stated  there  has  been  developed  a  method  of  standard- 
izing disinfectants  bj^  comparing  them  with  phenol.  By  this 
comparison  the  so-called  carholic  coefficient  is  determined. 
This  states  the  germicidal  power  of  the  given  substance  as 
compared  with  that  of  5%  carbolic  acid. 

The  test  is  limited  to  the  effect  of  the  germicide  upon  naked 
bacterial  cells  under  favorable  conditions  for  action.  The 
time  is  constant  and  the  strength  of  the  disinfectant  is  varied. 
A  24-hour  culture  of  B.  typhosus,  grown  in  bouillon  after 
having  been  transplanted  for  three  successive  days,  is  used 
as  a  test  organism. 

The  steps  in  making  the  Ricleal-Walker  test  for  standardiz- 
ing disinfectants  are  as  follows: 

(1)  Make  up  Standard  solution  of  5%  phenol. 

(2)  Prepare  three  test  tubes  using  5  c.c.  of  this  in  the  fol- 


DISINFECTION    AND    DISINFECTANTS  381 

lowing  dilutions:  1  to  90,  1  to  100,  1  to  110.     Tubes  1  inch 
in  diameter  are  used. 

(3)  Various  dilutions  of  the  substance  to  be  tested  are 
made  (5  c.c.  being  used  in  each  test  tube). 

(4)  i\ll  solutions  as  well  as  the  cultures  are  brought  to  20'^ 
C.  on  a  water  bath. 

(5)  Add  0.1  c.c.  of  culture  to  each  tube  at  intervals  of  30 
sec.  (Use  tubes  in  groups  of  5.) 

(6)  At  end  of  2^  minutes  begin  to  transplant  with  a  stand- 
ard loop  (4  mm.  No.  14  wire  U.  S.  Gauge)  to  broth  culture. 
Transplant  from  each  tube  at  the  end  of  2|-  minute  period. 

(7)  Make  a  second  transplanting  from  each  tube  when  it 
has  been  exposed  5  minutes. 

(8)  Incubate  transplants  48  hours  at  37°  C.  and  read  plus 
or  minus.  The  carbolic  coefficient  is  the  factor  obtained  by 
dividing  the  highest  dilution  of  the  unknown  disinfectant 
which  permitted  growth  of  both  the  2-J-  and  5  minutes  ex- 
posure by  the  highest  dilution  of  the  phenol  which  gave  the 
same  result. 

Physical  Agents  of  Disinfection. — The  following  list  enu- 
merates the  physical  means  of  disinfection  with  the  briefest 
comment  as  to  their  use  and  efficiency. 

(1)  Sunlight  is  an  active  germicide.  It  destroys  spores  as 
w^ell  as  bacteria.  The  blue-violet  and  ultra-violet  rays  pos- 
sess germicidal  power. 

(2)  Ultra-Violet  Rays  kill  spores  and  vegetative  cells. 

(3)  Electricity  may  kill  germs  either  by  thermal  or  electro- 
lytic action  but  it  is  not  adapted  to  general  or  practical  use. 

(4)  Burning  is  best  for  those  things  which  may  be  de- 
stroyed. 

(5)  Dry  heat,  150°  C.  for  one  hour  will  destroy  both  vege- 
tative cells  and  spores.  Dry  heat  lacks  penetration  and  is 
injurious  to  fabrics. 

(6)  Boiling  is  very  effective,  and  is  particularly  applicable 
to  the  disinfection  of  bedding,  body  linen,  towels,  fabrics  of 
many  kinds,  kitchen  and  table   ware,    cuspidors,    etc.     The 


382  HYGIENE :     DENTAL   AND    GENERAL 

efficacy  of  boiling  water  is  increased  by  the  addition  of  alco- 
hol, mercury  bichloride  or  alkaline  coal  tar  creosotes.  Ten 
per  cent  sodium  bicarbonate  will  prevent  rusting. 

(7)  Steam  is  satisfactory,  reliable,  quick  and  penetrating. 
It  sterilizes,  but  shrinks  woolens  and  injures  silks.  It  ruins 
leather,  furs,  skins  of  all  kinds,  rubber  shoes,  oilcloth  and 
articles  containing  rubber,  glue,  varnish  or  wood. 

GASEOUS  DISINFECTION 

Terminal  fumigation  was  formerly  practiced  following  al- 
most every  communicable  disease  but  of  late  this  practice  has 
been  largely  discontinued.  In  most  diseases  the  thorough  air- 
ing and  sunning  of  the  room  and  the  disinfection  of  all  arti- 
cles which  have  come  in  contact  with  the  patient  are  sufficient. 
There  has  been  a  false  sense  of  security  in  fumigation  and  it 
has  too  frequently  been  carelessly  carried  out  while  the  more 
important  disinfection  of  contaminated  material  has  been  neg- 
lected. Many  health  departments  continue  to  fumigate  after 
smallpox,  scarlet  fever  and  diphtheria,  but  even  this  is  likely 
to  be  abandoned.  If  it  is  done  it  should  be  certain  that  the 
room  is  made  tight  by  pasting  paper  over  cracks  and  holes 
and  that  the  gases  or  fumes  are  liberated  in  proper  quantity 
and  given  the  proper  time  for  action,  under  suitable  conditions 
of  temperature  and  moisture.  Fumigation  will  always  be  con- 
tinued to  kill  animals  wdiich  carry  the  germs  of  infectious 
disease.  Whether  rooms  are  fumigated  or  not  they  should 
always  be  renovated,  cleaned  and  aired  after  a  case  of  infec- 
tious disease.  Continuous  and  terminal  disinfection  of  con- 
taminated material  should  never  be  neglected. 

Formaldehyde  Gas. — Formaldehyde  is  the  most  generally 
applicable  gas  for  this  type  of  disinfection.  Neither  this  nor 
any  other  gas  has  great  power  of  penetration  and  its  use  must 
be  limited  to  surface  disinfection.  It  is  highly  irritating  but 
not  poisonous  to  man  and  does  not  injure  fabrics,  colors, 
metals  or  paintings.    Its  specific  gravity  is  about  that  of  the 


DISINFECTION    AND    DISINFECTANTS  SH-i 

air  and  it  diffuses  slowly.  It  is  not  an  insecticide.  It  com- 
bines with  decomposing  nitrogenous  substances  and  deodorizes 
them.     It  may  kill  spores  and  dry  organisms. 

Formalin  as  it  is  purchased  in  the  market  is  a  40  per  cent 
solution  of  formaldehyde  gas  in  water.  At  20°  C.  the  gas 
polymerizes  and  forms  trioxymethjdene,  a  Avhite  crj-'stalline 
substance. 

There  are  two  methods  of  liberating  or  driving  off  formal- 
dehyde gas  by  the  heat  liberated  from  chemical  reactions. 

In  the  Permanganafe-Fornialin  Method  25  grams  of 
KMnOi  are  added  to  500  c.c.  of  formalin  for  every  1000  cubic 
feet  of  air  space. 

In  the  Formalin-Lime- Aluminu'ni-Sulpliate  MetJiod  two  solu- 
tions are  used.  Solution  A  contains  150  grams  of  aluminum 
sulphate  dissolved  in  hot  water  (300  c.c).  Solution  B  con- 
tains 600  c.c.  of  Formalin.  Solutions  one  and  two  are  mixed 
and  poured  upon  2000  grams  of  unslaked  lime.  These  quan- 
tities give  the  proper  amount  of  gas  for  1000  cubic  feet  of  air 
space. 

Exposure  should  be  from  six  to  twelve  hours  for  disinfec- 
tion with  the  air  at  a  temperature  of  65°  F.  and  at  least  60  per 
cent  saturated  with  moisture. 

Besides  these  methods  of  liberating  formaldehyde  gas  there 
are  other  ways  of  disinfecting  with  it,  viz.:  (1)  the  autoclave 
under  pressure,  (2)  the  retort  without  pressure,  (3)  a  gener- 
ator or  lamp,  (4)  formaldehyde  and  dry  heat  in  partial 
vacuum,  (5)  spraying  formalin,  (6)  heating  paraform. 

Sulphur  Dioxide. — The  gas  SO2  depends  upon  a  combina- 
tion with  water  and  the  formation  of  sulphurous  acid 
(HoSOg)  for  its  disinfecting  action.  Its  efficiency,  therefore, 
depends  upon  the  moisture  present  in  the  air.  It  is  heavier 
than  air  and  readily  soluble  in  water.  It  does  not  penetrate 
nor  does  it  kill  spores. 

The  methods  of  fumigating  with  SOo  include:  (1)  The 
Pot  Method  by  which  sulphur  is  burned  in  a  metal  dish,  (2) 
The  Liquid  Sulphur  Dioxide  Method  in  which  liquid  SOo  pur- 


384  HYGIENE:     DENTAL   AND   GENERAL 

chased  in  tubes  is  allowed  to  evaporate,  (3)  The  Sulphur 
Furnace  method  by  which  the  fumes  are  poured  into  the  room 
or  space  to  be  fumigated. 

Five  pounds  of  sulphur  per  1000  cubic  feet  of  room  space 
are  required  for  germicidal  action ;  2  lbs.  per  1000  cubic  feet 
of  room  space  are  required  for  insecticidal  action.  One  pound 
of  sulphur  is  the  equivalent  of  2  lbs.  of  liquid  SO,. 

This  gas  is  used  primarily  as  an  insecticide  and  in  such 
capacity  needs  no  moisture.  When  so  used  in  a  house  mois- 
ture should  be  avoided  as  in  the  presence  of  water  it  rots 
fabrics,  injures  paintings  and  metallic  fixtures,  and  bleaches 
pigment.    The  reaction  time  ranges  from  6  to  12  hours. 

Oxygen  in  its  nascent  state  is  a  good  disinfectant.  It  kills 
by  combining  chemically  with  the  albuminous  matter  of  the 
bacterial  cell. 

Hydrocyanic  Acid  is  dangerous  because  it  is  so  deadly  a 
poison  for  man.  It  is  a  good  insecticide  but  not  a  good  ger- 
micide. It  is  not  toxic  to  plants,  but  is  particularly  toxic  to 
animals.  It  does  not  destroy  paintings,  furniture,  draperies 
or  carpets.  It  is  slightly  lighter  than  air,  invisible,  and  has 
the  odor  of  bitter  almonds. 

It  is  evolved  by  the  action  of  11280^  on  KCN:  (1|  parts 
H2SO4,  and  21/4  parts  H2O,  to  1  part  KCN).  Mix  the  water 
and  acid  together  then  add  potassium  cyanide.  Use  4  ounces 
to  5  ounces  of  KCN  per  1000  cubic  feet.  Sometimes  SO2  is 
used  with  HCN  because  the  odor  of  the  sulphur  will  give 
warning  of  the  more  deadly  gas.  It  is  most  used  to  rid  iso- 
lated buildings  and  ships  of  vermin. 


LIQUID  DISINFECTANTS 

Disinfecting  solutions  have  great  powers  of  penetration, 
whereas,  em.ulsions  do  not  penetrate  but  have  a  high  ger- 
micidal action  on  a  surface  where  the  suspended  material  of 
the  emulsion  accumulates. 


DISINFECTION    AND    DISINFECTANTS  385 

Mercuric  Chloride  (HgCL)  is  a  valuable  germicide,  de- 
structive to  all  microbial  life  in  weak  solutions.  It  kills  both 
germs  and  spores  but  does  not  deodorize.  It  is  highly  poison- 
ous. It  corrodes  metals  and  forms  insoluble  and  inert  com- 
pounds with  albuminous  matter. 

HgCL  is  a  white,  volatile  and  crystalline  substance,  dis- 
solving in  16  parts  of  cold  water  and  3  parts  of  boiling  water. 
It  is  highly  soluble  in  alcohol.  HCl,  NaCl,  and  NH^Cl  aid 
in  its  solution.  It  is  decomposed  by  lead,  copper  and  other 
metals.  It  is  used  in  dilutions  of  1 :500  or  1 :1000,  A  solu- 
tion of  1:1000  kills  vegetative  cells  in  1/2  hour.  A  1:500 
dilution  kills  spores  in  1  hour.  A  1 :1000  solution  =  1  gm. 
per  liter  or  1  dram  per  gal. 

Formalin  is  a  forty  per  cent  solution  of  formaldehyde  gas 
in  water.  It  acts  well  in  the  presence  of  albuminous  matter 
and  is  not  injurious  to  most  articles.  It  is  a  true  deodorant 
and  not  very  poisonous  to  man  although  it  is  unstable  and 
polymerizes  in  cold  weather  to  form  trioxymethylene.  Hot 
formalin  attacks  iron  and  steel  but  does  not  attack  copper, 
brass,  nickel,  or  zinc.  It  has  no  detrimental  effect  on  fibers 
and  does  not  bleach  colors  but  it  renders  leather  and  furs 
brittle.  A  ten  per  cent  solution  of  formaldehyde  is  equiv- 
alent to  a  1  to  500  solution  of  HgCh  and  superior  to  5  per 
cent  phenol.  Feces  are  deodorized  (and  disinfected  Avhen 
thoroughly  mixed)  by  10  per  cent  formalin. 

Potassium  Permanganate  (KMnO^)  has  limited  application 
since  it  is  readily  reduced  by  organic  matter  but  it  is  a  good 
germicide  in  surgical  practice.  It  is  a  dark  purple,  crystalline 
substance  and  has  a  sweet  astringent  taste.  Probably  free 
nascent  oxygen  is  the  true  disinfecting  agent.  It  kills  vegeta- 
tive organisms  and  spores.  It  is  soluble  in  16  parts  cold  water 
and  2  parts  boiling  water. 

Lime  is  one  of  the  best  and  cheapest  disinfectants  we  have. 
It  is  used  as  slaked  lime  or  as  chlorinated  lime  for  destroying 
infection  in  organic  matter.  CaO  is  obtained  by  calcinating 
or  heating  native  CaCOg  (chalk,  limestone,  or  marble") .     Tbe 


386  HYGIENE:     DENTAL   AND   GENERAL 

addition  of  water  to  calcinated  lime  produces  slaked  lime 
which  may  be  used  for  germicidal  purposes.  Slaked  lime 
[Ca  (0H)o]  is  a  mixture  of  one  pint  of  water  for  every  2 
lbs.  of  calcinated  lime.  Lime  absorbs  about  one-half  its 
weight  of  water.  Freshly  slaked  lime  should  be  used,  else 
CO2  is  absorbed  from  the  air,  and  the  slaked  lime  becomes 
inert  CaCOg. 

Whitewash  is  slaked  lime  diluted  with  ten  parts  of  water 
and  mixed  with  glue.  It  is  valuable  for  destroying  spore  free 
bacteria  that  have  lodged  on  the  surfaces  of  rooms,  barns, 
stables,  etc. 

Milk  of  Lime  is  slaked  lime  diluted  with  about  4  times  its 
volume  of  water  to  a  thick  creamy  consistency.  It  is  useful 
for  the  disinfection  of  excreta  and  privy  vaults.  Freshly 
slaked  lime  must  be  used  in  its  preparation.  If  older  than 
a  few  days  it  is  probably  worthless. 

Ten  per  cent  Ca  (OH) 2  solution  kills  vegetative  germs  in 
a  few  hours;  a  3  per  cent  Ca  (OH),  solution  kills  typhoid 
in  one  hour;  a  20  per  cent  Ca  (OH) 2  solution  will  sterilize 
feces  in  one  hour. 

DISINFECTION  IN  DENTAL  PRACTICE 

Hands.- — All  dirt  should  be  removed  and  the  tissues  kept 
in  a  soft  condition ;  short  nails  are  easier  to  keep  clean.  Scrub 
with  soap  and  water  using  a  brush,  and  rinse  ojff  with  70  per 
cent  alcohol.  Solutions  of  HgCla  are  more  or  less  injurious 
to  the  hands  but  are  often  used.  A  2  per  cent  solution  of 
phenol  followed  by  the  use  of  a  deodorant  to  remove  odor 
may  be  used. 

Materials. — Instruments  should  be  boiled  and  wiped  off 
with  alcohol.  Boiling  water  is  used  for  broaches,  and  broach 
holders,  burnishers,  burs,  clamps,  chisels,  drills,  excavators, 
explorers,  hand  pliers,  pluggers,  reamers,  elevators,  scissors, 
scalers  and  spatulas.  Mirrors  may  be  washed  in  hot  water 
and  wiped  in  alcohol.     The  glass  table  or  instrument  rest 


DISINFECTION    AND    DISINFECTANTS  387 

should  be  washed  with  alcohol  after  each  use  to  prevent  spots 
of  blood  or  mucus  from  getting  onto  instruments.  Chip 
blower  tips  should  be  passed  through  the  flame  before  using. 
Cotton  rolls,  cottonoid  napkins,  gauze  and  cotton  pellets  should 
be  kept  in  closed  glass  jars.  The  engine  hand  piece  may  be 
boiled  in  green  soap  solution  and  should  always  be  wiped 
with  alcohol  before  using.  Cotton  and  gauze  materials  may 
be  sterilized  by  dry  heat  and  kept  in  sealed  packages. 

With  the  development  of  a  more  widespread  and  popular 
knowledge  of  bacteria  and  communicable  disease  many  people 
watch  both  the  personal  hygiene  of  the  dentist  and  his  care 
of  the  instruments  more  closely  than  he  suspects. 

The  OiRce  should  be  kept  well  aired  and  free  from  dust. 
Articles  handled  or  mouthed  by  patients  who  may  have  an 
infectious  disease  should  be  burned  or  disinfected.  Furniture 
handled  by  them  may  be  washed  in  5  per  cent  phenol.  Nap- 
kins should  be  boiled.  Paper  cups  and  paper  cuspidors 
should  be  used  and  burned. 


BIBLIOGRAPHY 


The  following  list  of  publications  is  designed  for  a  brief 
working  bibliography  and  is  arranged  according  to  chapter 
topics. 

GENEEAL 

Bergey,  D.  H. :     Principles  of  Hygiene,  Philadelphia,  Pa.,  6th  Edition, 

W.  B'.  Saunders  Co. 
Egbert,  Seneca :     Hygiene  and  Sanitation,  Philadelphia,  Pa.,  1919,  Lea 

&  Febiger. 
Fisher,  I.,  and  Fisk,   E.  L. :     How  to  Live,   New  York,  1915,   Funk  & 

Wagnalls  Co. 
Gardner,  Fletcher :     Practical  Sanitation,  St.  Louis,  1916,  2nd  Edition, 

C.  V.  Mosby  Co. 

Lee,  Eoger  I.:     Health  and  Disease,  1917,  Little,  Brown  &  Co.,  Boston. 
Pyle,  W.  L. :     Pyle's  Manual  of  Personal  Hygiene,  Philadelphia,  Pa., 

7th  Edition,  W.  B.  Saunders  Co. 
Rosenau,  M.   J. :     Preventive  Medicine   and  Hygiene,  New  York,  1916, 

D.  Appleton  &  Co. 

Stiles,  P.  G. :  Human  Physiology,  Philadelphia,  Pa.,  1919,  W.  B.  Saun- 
ders Co. 

Winslow,  C.-E.  A. :     Handbook  of  Health  in  War  and  Peace,  New  York,  . 
1917,  The  Century  Co. 

DENTAL  HYGIENE 

Black:  Operative  Dentistry,  Chicago,  1917,  Medico-Dental  Publishing 
Co. 

Black:  Special  Dental  Pathology,  Chicago,  1915,  Medico-Dental  Pub- 
lishing Co. 

Braekett,  C.  A. :  Care  of  the  Teeth,  Cambridge,  Mass.,  1915,  Harvard 
University  Press. 

Endelman  and  Wagner:  General  and  Dental  Pathology,  St.  Louis, 
1920,  C.  V.  Mosby  Co. 

Head,  Joseph:  Mouth  Hygiene,  Philadelphia,  Pa.,  1920,  W.  B.  Saun- 
ders Co. 

Hecker,  Friedrich:  Pyorrhea  Alveolaris,  St.  Louis,  1913,  C.  V.  Mosby 
Co. 

389 


390  HYGIENE:     DENTAL   AND   GENERAL 

Hutchiuson :     Food  and  Dietetics,  New  York,  William  Wood  &  Co. 

Pickerill:  Prevention  of  Dental  Caries  and  Oral  Sepsis,  Philadelphia, 
Pa.,  S.  S.  White  Co. 

Prinz :  Dental  Materia  Medica  and  Therapeutics,  St.  Louis,  5th  Edi- 
tion, 1917,  C.  V.  Mosby  Co. 

Todd,  T.  Wingate:  Mammalian  Dentition,  St.  Louis,  1918,  C.  V.  Mosby 
Co. 

NUTEITION 

Cannon,  Walter  B. :     Bodily  Changes  in  Pain,  Hunger,  Fear  and  Eage, 

New  York,  1915,  D.  Appleton  &  Co. 
HoweU,  W.  H.:     Textbook  of  Physiology,  Philadelphia,  Pa.,  1914,  W. 

B'.  Saunders  Co. 
Lusk:     Fundamentals  of  Nutrition,  New  Haven,  Conn.,  1914,  Yale  Uni- 
versity Press. 
Lusk:     Elements  of  the  Science  of  Nutrition,  Philadelphia,  Pa.,  1917, 

W.  B.  Saunders  Co. 
McCoUum:     Newer  Knowledge  of  Nutrition. 
Sherman:     Chemistry  of  Foods  and  Nutrition,  New  York,  1911,  Mac- 

Millan  Co. 
Taylor:     Digestion   and   Metabolism,   Philadelphia,      Pa.,   1912,   Lea   & 
Febiger. 
Special  pamphlets  on  Diet  may  be  secured  from  the  United  States 
Health  Service,  from  the  Children's  Bureau  of  the  United  States  Depart- 
ment of  Labor,  and  from  many  State  Departments  of  Health, 

HYGIENE  OF  THE  CENTRAL  NERVOUS  SYSTEM 
Courtney:     The  Conquest  of  the  Nerves,  New  York,     1911,  MacMillan 

Co. 
Lickley:     The   Nervous  System,  New  York,   1912,  Longmans,   Green  & 

Co. 
Loeb:     Comparative  Physiology  of  the  Brain,  The  Science  Series,  New 

York,  1900,  G.  P.  Putnam's  Sons. 
Stiles,  Percy  G.:     The  Nervous  System,  Philadelphia,  Pa.,    1914,  W.  B. 

Saunders  Co. 
Thomson :     Brain  and  Personality,  1907,  Dodd,  Mead  &  Co. 

THE  HYGIENE  OF  REPRODUCTION 
Castle,  W.  E. :     Genetics  and  Eugenics,   Cambridge,  Mass.,   1916,  Har- 
vard University  Press. 
Conklin,  E,   G. :     Heredity  and  Environment,   Princeton,   N.   J.,      1915, 

Princeton  University  Press. 
Davenport:     Heredity  in  Relation  to  Eugenics,  New  York,  1911,  Henry 
Holt  &  Co. 


BIBLIOGRAPHY  391 

Exner,  M.  J.:     Rational  Sex  Life  for  Man,  1917. 

Galton:     Eugenics,  Its  Definition,  Scope  and  Science,  1903. 

Galton:     Hereditary   Genius,   1869. 

Poponoe  and  Johnson:     Applied  Eugenics,  Xew  York,  1918,  MacMillan 

Co. 
Stopes:     Married  Love,  Fifield,  Loudon. 

THE   XEW  SCIENCE   OF  DISEASE   PREVENTION 

Councilman :     Disease  and  Its  Causes,  New  York,  1913,  Henry  Holt  & 

Co. 
Hamilton,  Lady  Claud:     Louis  Pasteur — His  Life  and  Labors,   (by  his 

son-in-law),  translated  from  the    French,  New  York,  1885,  D.  Ap- 

pleton  «fc  Co. 
Sedgwick:     Principles  of  Sanitary  Science  in  Public  Health,  New  York, 

1914,  MacMillan  Co. 

IMMUNITY 

Hiss,  P.  H.,  Jr.,  and  Zinsser,  Hans:     A  Textbook  of  Bacteriology,  New 

York,  1918,  D.  Appleton  &  Co. 
Zinsser,  Hans:     Infection  and  Resistance,  New  York,  1916,  MacMiUan 

Co. 

SPECIFIC  DISEASES 

Rosenau,  M.   J.:     Preventive  Medicine  and  Hygiene,   New  York,   1916, 

D.  Appleton  &  Co. 
Stokes:     Today's  World   Problem   in   Disease   Prevention,   1919,   U.   S. 

Public  Health  Service. 
U.  S.  Public  Health  Service  Reports  on  Influenza. 
Special   Articles   on   Influenza   and   Articles   on   Venereal .  Disease,    The 

American  Journal     of  Public  Health,  Boston. 

PUBLIC  HEALTH  ADMINISTRATION 

McNutt,  J.  Scott:  Manual  for  Health  Officers,  1915,  John  Wiley  & 
Sons. 

Overton  and  Denno:  The  Health  Officer,  New  York,  1919,  W.  B.  Saun- 
ders Co. 

Whipple,  G.  C:     Vital  Statistics,  1919,  John  Wiley  Sc  Sons. 

WATER  SUPPLY 

American  Public  Health  Association,  Standard  Methods  for  Water  Anal- 
ysis, 1920. 

Prescott  and  Winslow:  Elements  of  Water  Bacteriology,  New  York, 
1913,  John  Wiley  &  Sons. 


392        -  HYGIENE  :     DENTAL   AND   GENERAL 

Turueaure  and  Eussell:     Public  Water  Supplies,  New  York,  1914,  Jolm 

Wiley  &  Sous. 
Weston  aud  Turner:     The  Digestion  of  a  Sewage  Filter  Effluent  by  a 

Small  Stream,  Contributions  from  Sanitary  Eesearch  Laboratory, 

Vol.  X,  Massachusetts  Institute  of  Technology,  Cambridge,  Mass. 
Whipple,  G.  C. :     Microscopy  of  Drinking  Water,  New  York,  1914,  John 

Wiley  &  Sons. 
Woodman  and  Norton:     Air,  Water  and  Food,  1914,  John  Wiley  &  Sons. 

FOOD  CONTEOL 

Parker,  Horatio  N.:     Milk  Supply,  New  York,   1917,  McGraw-Hill  Co. 

Rosenau,  M.  J. :  The  Milk  Question,  Bioston,  Mass.,  1912,  Houghton 
Mifflin  Co. 

Savage,  W.  G.:  Milk  and  the  Public  Health,  New  York,  1912,  Mac- 
Millan  Co. 

Stiles,  Percy  G. :  Nutritional  Physiology,  Philadelphia,  Pa.,  3rd  Edi- 
tion, W.  B.  Saunders  Co. 

Eeport  of  the  Commission  on  Milk  Standards,  New  York  Milk  Commit- 
tee, Public  Health  Eeports,  May  10,  1912. 

WASTE  DISPOSAL 

Metcalf  and  Eddy:  American  Sewerage  Practice,  New  York,  1916,  Mc- 
Graw-Hill Co. 

Public  Health  Bulletin,  No.  101 :  The  Treatment  of  Sewage  from  Sin- 
gle Houses  and  Small  Communities,  Dec,  1919,  U.  S.  Public 
Health  Service. 

Kinnicutt,  Winslow  and  Pratt:  Sewage  Disposal,  New  York,  1910, 
John  Wiley  &  Sons. 

See  also  special  references  at  the  end  of  Chapter  XIII. 

SCPIOOL  HYGIENE 

Berkowitz,    J.    H. :     Standardization    of    Medical    Inspection    Facilities, 

1919,  Bulletin  No.  2,  United  States  Bureau  of  Education. 
Clark,    Taliaferro:     School    Medical    Inspection,    Sept.,    1919,     Eeprint 

No.  554,  U.  S.  Public  Health  Report. 
Gulick  and  Ayres:     Medical  Inspection  of  Schools,  New  York  Charities 

Publishing  Committee. 
Health  Work  Bulletin  No.   50,  part   7:     The  Public  School  System   of 

Memphis,   Tenn.,   1919:      United  States  Bureau  of  Education. 
Hogarth,  A.  H. :     Medical  Inspection  of  Schools,  New  York  and  London, 

1909,  Oxford  University  Press. 
Hyatt,  T.  P.:      The  Eelationship  of  Dental  Conditions  to  the  Physical, 

Moral,  and  Mental  Development  of.  a  Child,  1919,  Dental  Cosmos. 


BIBLIOGRAPHY  393 

Penusylvania  Department  of  Health,  Engineering  Division :     Manual  of 

School  Sanitation,  Aug.,  1919. 
Smith,  John  H. :     Co-operation  in  the  Control  of  Communicable  Diseases 

Among  School  Children,  New  York  State  Department  of  Health, 

1918. 

INDUSTEIAL  HYGIENE 

Golclmark  and  Brandeis:  Fatigue  and  Efficiency,  New  York,  1912, 
Charities  Publishing  Committee. 

Meek,  Harry  E. :  Industrial  Medicine  and  Surgery,  1919,  Philadelphia, 
W.  B.  Saunders  Co. 

Oliver,  Thomas:  Diseases  of  Occupation,  New  York,  1909,  E.  P.  Dut- 
ton  &  Co. 

Price,  G.  M. :  The  Modern  Factory,  New  York,  1914,  .John  Wiley  & 
Sons. 

Health  of  Munition  Workers,  Committee  Reports,  His  Majesty 's  Sta- 
tionery Office,  London,  1917  and  1918. 

Studies  in  Vocational  Diseases,  published  by  the  United  States  Public 
Health  Service. 

Special  pamphlets  are  available  from  the  United  States  Public  Health 
Service,  Washington,  D.  C,  and  from  many  of  the  State  Depart- 
ments of  Health. 

Thompson,  W.  G. :  The  Occupational  Diseases,  New  York,  D.  Appleton 
&  Co. 

VENTILATION,  HEATING  AND  LIGHTING 
Carjsenter,   E.   C. :     Heating  and  Ventilating  of  Buildings,  New  York, 

1915,  John  Wiley  &  Sons. 
Henderson:     Paper    read    before    Fifteenth    International    Congress    on 

Hygiene  and  Demography. 
Hill,  Leonard :     Journal  of  Physiology,  London,  1910. 
Hoffman   and   Raber:     Handbook   for   Heating   and   Ventilating   Engi- 
neers, 1913. 
Pfluge :     Zeitschrift    fiir    Hygiene    and   Infections-krankheiten,    Leipsic, 

1905,  p.  363. 
Winslow,  C.-E.  A.,  and  others:     Standards  for  Measuring  the  Exhaust 

Systems  in  Polishing  Shops,  Reprint  Na.  509,  U.  S.  Public  Health 

Reports,  March  7,  1919. 
Report  of  the  New  York  Ventilating  Commission,  New  York,  1915. 
The  Science  of  Ventilation  and  Open-Air  Treatment,  published  by  His 

Majesty's  Stationery  Office,  London,   1919. 

DISINFECT^AISTTS 
Rosenau,  M.  J. :     Preventive   Medicine  and  Hygiene,   New  York,   191(5, 
D.  Appleton  &  Co. 


INDEX 


Abnormalities,  inherited,  88 
Accident  insurance,  306 

prevention,  310 
Acid   poisoning,    321 
Actinomycosis,   343 
Action,  hygiene  of,  54 
Activated  sludge,  250 
Activity,  bodily,  54 
Acute      infectious      conjunctivitis, 

343 
Adenoids,   24 
Administration,  local  health,   205 

of  health  in  industry,  307 

of  school  hygiene,  281 

state  health,  202 
Adulteration   of  food,  209 
Aerobic  purification  of  sewage,  246 
Agglutinins,  136 
Air,  cooling  of,  335 

quality  of,  323 

testing,    327 

washing  and  humidifying,  334 
Alcohol,  76 
Alveolar  process,  28 
Amboceptor,  137 
Amebic   dysentery,   351 
An^robic    purification    of    sewage. 

Anaphylaxis,  133 
Anchylostomiasis,  344 
Antitoxins,  135 

discovery  of,   117 
Anthrax,  345 

immunity  in,  115 
Antiseptics,  378,  379 
Artificial  ventilation,  332 
Asepsis,  378 
Assimilation,  48 

Authority    for    health    administra- 
tion, 188 
Autointoxication,  49 


B 

Bacillary  dysentery,  352 
Bacillus  botulinus,   222 
Bacteriological  purification  of  sew- 
age, 246 
Balanced  diet,  39 
Bathing,  65 

Benzene  poisoning,  321 
Beri-Beri,  38 
Bodily  defects,  75 
Body  wastes,  elimination  of,  49 
Botulism,  222 
Breathing,   64 
Broad  St.  well,  118 


Calorie  requirement,  40 

Carbohydrates,  35 

Caries,  144 

Carriers,  130,  340 

Central    nervous    system,    hygiene 

of,  68 
Cesspool,  251,  263 
Cerebrospinal  meningitis,  347 
Chemical  closet,  245,  262 
Chemical  precipitation   of   sewage, 

245 
Chemical    purification    of    sewage, 

244 
Chicken  pox,  348 
Child  labor,  305 

Child's  ten  commandments,   1U6 
Chlorination  of  water,  241 
Chlorine  in  water  analysis,  234 
Cholera,  348 
Cleaning,  340 
Clothing,  66 
Cocoa,  77 
Cotfee,  77 

Colds,  cause  of,  181 
Color  blindness,  87 
Comfort  meter,  330 
Common  cold,  180 


395 


396 


INDEX 


Common  law,  196 
Communicable   diseases,   108,   165 

control  of,  339 
Complement,  137 
Concentration,  mental,  69 
Conjunctivitis,  infectious,  343 
Conn,  H.  W.,  121 
Constipation,  51 
Contact,  341 
Contact  beds,  265 
Contact   of  teeth,   19 
Cooling  air,  335 

D 

Dairy  score  card,  214 
Defects,   bodily,   75 
Defective  school  children,  275 
Defective  vision,  285 
Deformities,  of  face  and  jaw,  24 

of  feet,  62 
Dental  care  of  school  children,  286 
Dental  floss,  159 
Dental  hygiene,  17 
Dental  hygienist,   153 
Dental     instruments,     disinfection 

of,   386 
Dentin,  structure  of,  27 
Dentistry,  industrial,  315 
Delousing,  341 
Deodorants,  378,  379 
Dengue,  350 
Deposits  on  teeth,  152 
Diet,   33 

and  tooth  decay,  147 

balanced,   39 

varied,  42 
Dietary   diseases,   38 
Digestion,  42 
Diphtheria,  350 

and  antitoxin,  117 
Disease  reactions,  130 
Diseases,   communicable,   108,   165, 
339 

dietary,  38 

industrial,   319 

inherited,  88 

prevention  of,  108 

prevention  in  industry,  318 

systemic,  and  septic  teeth,  161 

theories  of,  108 
Disinfectants,  licjuid,  384 

standardization  of,  380 
Disinfectant,  the  ideal,  380 


Disinfection,  341,  379 

and  disinfectants,  378 

control  of,   379 

gaseous,  382 

in  dental  practice,  386 

natural,  380 

physical  agents  of,  381 
Disposal  of  garbage,  267 

of  manure,  269 

of  sewage,  243 
Dreams,  72 

Drugs  and  immunity,   128 
Dysentery    (amebic),  351 
Dysentery  (bacillary),  352 

E 

Emotions  and  digestion,  42 

and  the  nervous  system,  74 
Emotions,  hygiene  of,  45 
Enamel,  structure  of,  26 
Endotoxins,  132 
Epidemic  of  Broad  St.  well,  118 

typhoid  from  oysters,  121 
Environment  and  heredity,  91 
Eugenics  (see  heredity) 
Exercise,  54 

rhythm  in,  58 

types  of,  57 
Exposure  to  wet  and  cold,  127 


F 


Factory  insijection,   306 
Fatigue  and  immunity,   127 

in  industry,  305 
Fats  in  diet,  36 
Favus,  109,  353 
Federal  health  agencies,  194 

public  health  functions,  188 
Feeble-mindedness,  93 
Feet,  deformities  of,  62 
Fermentation  and  disease,  109 
Figure,   59 

Filtration  of  water,  240 
Fly  breeding,  prevention  of,   263 
Food,  adulteration  of,  209 

control,   209 

in  industry,  311 

l^oisoning,  51 

prepared,  223 

sanitation,   213 


INDEX 


397 


Foi'maldehyde  gas,  382 
Formalin,  385 
Fumigation,  379 

G 

Garbage  disposal,  267 
Gaseous  disinfection,  382 
German  measles,   353 
Germicides,   378 
Gingivte,   29 

care  of,  149 
Gingivitis,    151 
Glanders,  354 
Good  air  defined,  323 
Gonorrhea,  355 
Ground  water,  228 
Gums  and  gingivae,  care  of,  149 

H 
Habit,  70 

Hands,  disinfection  of,  386 
Head,  carrying  forward,  60 
Health  education  in  industry,  318 

officer,   207 

societies,   207 
Heredity,  80 

and  conduct,  93 

and  environment,  91 

mental,  90 
HiiDpocrates,  109 
Hookworm,  344 
Hours  of  worlv,  304 
Humidifying  air,  333 
Hydrocyanic  acid,  384 
Hygiene,  dental,  17 

industrial,  301 

ocular,  63 

of  action,  54 

of  central  nervous  system,  ('iS 

of  the  emotions,  45 

of  mouth,  18 

of  nutrition,  33 

of   reproduction,    80 

of  sex,  104 

I)ersonal,  divisions  of,  17 

preventive,  123 

scliool,  274 
Hvgienist,  the  dental,  153 
Ilygvodeik,  329 


Immunity,   acquired,   129 

active  and  passive,  130 

defined,  125 

essential  facts   of,   125 

in  anthrax  and  rabies,  115 

local,  129 

natural,  128 

nonspecific,  127 
specific,   128 

theories  of,  138 
Imhoff   tank,   264 
Incineration  of  garbage,  268 
Indigestion,    emotional,    45 
Industrial  accident  insurance,   306 

dentistry,  315 

diseases,  319 

health  administration,   307 
"  hygiene,    301 

medical  activities,  312 

sanitation,  311 
Influenza,  184 

cause  of,  185 

control  of,  186 

immunity  to,  186 

morbidity    and    mortalitv    rates, 
185 
Infant  care,  100 

standards  of,   103 
Inherited   diseases  and   abnormali- 
ties,  88 
Injunction,  197 
Inorganic   salts   in    diet,   37 
Intermittent    sand    filtration,    247 
Investing  tissues   of  teeth,  28 
Isolation,  342 
Insurance,  accident,  306 


Koch,    112 


Lawrence   experiment   station,   249 
Laws,  public  health,  195 

pure  food,  210 
Lead  jioisoning,  319 
Leprosy,  356 
License,  nature  of,  196 
Lighting,  337 
Lime,  385 
Lister,   112 

Local  health  administration,  205 
Lysius,  137 


398 


INDEX 


M 

Mastication,   47 

and  salivary  secretion,  31 
Maternity  care,  standards  of,  98 
Malaria,  357 
Manure  disposal,  269 
Measles,  358 

German,  353 
Meat,  sanitation  of,  222 
Mechanical  filter,  240 

ventilation,  332 
Medical  activities  in  industry,  312 
Mendelian   inheritance,    80 
Meningitis,  cerebrospinal,  347 
Mental  concentration,   69 
Mentality  and  heredity,  90 
Mercuric   chloride,   385 
Mercury  poisoning,  321 
Miles'  process,   246 
Milk,    cow's,    composition    of,    213 

graded,  218 

human,  composition  of,  39 

in  diet,  39 

New  York  regulations,  220 

remade,  219 

sanitation  of,  213 
Milk  of  lime,  386 
Misbranding,   212 
Mouth,  care  of  the  child's,  161 

hygiene,  18 

washes,  160 
Moisture  in  air,  326 
Mucus,  31 
Municipal    health    administration, 

205 
Mumps,  359 

N 

Natural   disinfection,   380 

ventilation,  331 
Nervous  system,  hygiene   of,  68 
Neurasthenia,   73 
Neurasthenic,  the,  78 
Nightsoil,  final  disposal  of,  262 
Nitrogen  cycle,  233 
Nitrogenous  foods,  35 
Nuisance,  197 
Nutrition,  hygiene  of,  33 

O 

Obesity,   52 
Occlusion  of  teeth,  19 
Ocular  hygiene,  63 


Odors  in  air,  326 

Office,    disinfection   of,   387 

lighting,   338 
Opsonins,  132 

Oral  defects  and  immunity,  128 
Oral  prophylaxis,  144 
Orthodontia,    20 
Overwork,  74 
Oxidation,  49 
Oxygen,  nascent,  384 


Pacifying    devices,    25 
Paratyphoid  bacilli  in  meat,  222 

fever,  360 
Pasteur,  109,  111 
Pasteurization,  218 
Patent  medicines,  77 
Pellagra,  38 

Peridental  membrane,  28 
Permits,  196 

Personal  hygiene,  divisions  of,  17 
Phagocytosis,  132 
Physical    examination   in   industry, 
312 

of  school  children,  277 
Phosphorus  poisoning,   320 
Pit  privy,  259 
Plague,   361 
Pneumonia,  364 
Poisoning,  acid,  321 

benzene,  321 

food,  51 

lead,  319 

mercury,   321 

phosphorus,  320 

ptomaine,  223 
Police  power,  196 
Poliomyelitis,  362 
Polymeter,  330 
Posture,  59 

Potassium  permanganate,  385 
Power  of  discretion,  196 
Precipitins,  136 

Prepared  food,  sanitation  of,  223 
Prenatal  care,  95 
Preschool    child,    standards,    103 
Preventive  hygiene,  123 

medicine,  history  of,  113 

sanitation,  history  of,   117 


INDEX 


J 


399 


Privy,  deodorizing  the,  263 

the  pit,  259 

the  receptacle,  260 
Prophylactic    treatment    of    teeth, 

153 
Prophylaxis,  oral,  144 
Proteins  in  diet,  35 
Fsychrometer,  the  sling,  329 
Ptomaine  poisoning,  223 
Ptyalin,  31 
Public  health  administration,  188 

laws,   195 
Pure  food  laws,  210 


Quarantine,  342 

E 

Eabies,  363 

Eabies,  immunity  in,  115 

Eeactive  phenomena,  132 

Eeceptacle  privy,  260 

Eegulations,  health,  197 

Eelative  humidity,  328 

Eenovation,  342 

Eeproduction,  hygiene  of,  80 

Eesistanee   and  hygiene,   123 

Eest  after  eating,  48 

Eickets,  39 

Eocky  Mountain  spotted  fever,  364 

Eound  shoulders,  59 

Eural  sanitation,  254 

S 

Saliva,  30 

Sand  filtration  of  sewage,  266 

of  water,  240 
Sanitation,  industrial,   311 

of  food,  213 

of  school  buildings,  296 

preventive,   117 

rural,  254 
Scarlet  fever,  365 
School  children,  dental  care  of,  286 

physical  examination  of,  277 

standard  requirements  for,  299 

treatment  of  defects,  280 
School  dental  clinics,  291 

health  control,  276 
School  hygiene,  274 

administration  of,  281 

how  taught,  294 


School    hygiene — Cont  'd. 
medical  personnel  for,  276 
scope  of,  275 
School  sanitation,  296 
Score  card  for  food  establishments, 

224 
Scurvy,  38 

Sedgwick-Eafter  process,  235 
Self  purification  of  streams,  236 
Sepsis,  378 

Septic  sore  throat,  366 
Septic  tank,  251,  264 
Sewage  disposal,  243 
farming,  247 

purification,  limitations  of,  253 
purification,  table  of,  255 
Sex  education,  104 
Sex,  how  determined,  86 

hygiene,  104 
Sex-linked  characters,   87 
Side  chain  theory,  139 
Sleep,  70 

Sling  psychrometer,   329 
Sludge  disposal,  266 
Smallpox,  367 

and  vaccination,  114 
Soakage  pit,  266 
Societies,   health,    207 
Spinal  curvatures,  62 
Sprinkling  filters,  250 
Standardizing  disinfectants,  380 
Standards,  for  infant  care,  103 
for  maternity  care,  98 
for  preschool  child,  103 
for  school  children,  299 
Starches  in  diet,  35 
State   department   of   health,   divi- 
sions   of,    203 
department  of  health,  organiza- 
tion, 198 
health   administration,   198 
health  functions,  195 
Statutory  law,  196 
Sterilization,  378 
Stimulants,  76 
Storage  of  water,  236 
Straddle  trench,  258 
Structure  of  teeth,  25 
Subsurface    irrigation,    265 
Sugars  in  diet,  35 
Sulphur  dioxide,   383 
Sunday  observance,  73 
Surface  irrigation,  265 
water,  228 


400 


INDEX 


Susceptibles,   342 
Sydenham,  109 
Syphilis,  174,  368 

prevention  of,  178 

transmission  of,  177 

T 

Tapeworms,   223 

Taenia    223 

Tank,  Imhoff,  252,  264 

Tank,  septic,  251,  264 

Tea,   77 

Teeth,  contact  and  occlusion,  19 

daily  care  of,  155 

development  of,  21 

form  and  arrangement  of,  18 

function  of,  21 

investing  tissues  of,  28 

method  of  brushing,  156 

septic,  161 

structure  of,  25 
Temperature,  326 
Testing  air,  327 
Tetanus,  369 
Thumb   sucking,   25 
Theories  bf  disease,  108 

of  immunity,  138 
Thermometer,  wet  bulb,  328 
Tick  fever,  364 
Toxins,  131 

Toothbrush,   care   of,   159 
Toothpicks,  159 

Tooth  powders  and  pastes,  160 
Tooth-cleansing  foods,  161 
Trachoma,  370 
Trichina  spiralis,  222 
Trichinosis,  222,  371 
Trickling  filters,  265 
Tuberculosis,  167 

other  than  pulmonary,  373 

prevention  and  control,  171 

pulmonary,  371 

transmission  of,  169 


Two-story  tank,  250 
Typhoid  fever,  373 

epidemic  from  oysters,   121 
Typhus  fever,  374 

U 

Under-eating,  52 

and  immunity,  128 
U.   S.   Public  Health   Service,   191 

V 

Vaccination,  history  of,  114 
Varied  diet,  42 
Vaughan,  133 

Ventilation,    artificial    or    mechan- 
ical,  332 

and  heating,  330 

economic  value  of,  336 

heating  and  lighting,  323 

natural,  331 
Vitamines,  37 
Vision,  defective,  285 

W 

Walking,  58 

Water,  analysis  of,  230 

filtration  of,  240 

in  the  diet,  34 

in  the  saliva,  31 

pui'ification  of,  236 

supply,   226 

sources  of  supply,   228 

with  meals,  48 
Waste   disposal,    243 
Whitewash,   386 
Whooping  cough,   375 
Women  in  industry,  305 
Work,  change  of,  72 


Yellow  fever,  376 


T852 


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is  ^ue  t/n  the  date 


expiration  of  a  iiefini/r"'"  T'^  indicated  below   or  af  fv, 
P-vided  by  th/rul^TtrLt"  '"^  '^^^  °^  bo;r:;it  L 
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